Climate Change and Climate Variability, and Their Impact on Extreme Events

A special issue of Atmosphere (ISSN 2073-4433). This special issue belongs to the section "Climatology".

Deadline for manuscript submissions: closed (30 June 2023) | Viewed by 33861

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Disaster Prevention Research Insitute, Kyoto University, Uji, Kyoto 611001, Japan
Interests: climate modeling; extreme events; dynamical downscaling; land use and land cover change; numerical weather prediction; statistical method applications; remote sensing applications and GIS
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Department of Geography, Delhi School of Economics, University of Delhi, Delhi 110007, India
Interests: Indo-Pacific variability; climate variability and societal impacts; climate change and river hydrology; agriculture; hydroclimate; disaster risk reduction; trend analysis
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Special Issue Information

Dear Colleagues,

In the present scenario, climate change and climate variability are of great concern around the world, particularly their impact on extreme weather events, which consequently affect all sectors, including habitat, economy, health, water, and agriculture. Thus, understanding the pattern of climate change and climate variability has been the focus of many researchers, and many efforts are being made to better frame the consequences of their future impacts. This Special Issue of Atmosphere seeks contributions on observational and numerical modeling studies to enhance the understanding of the global or regional climate patterns and variations over time in some measures of climate. This issue also encourages articles that discuss regional or global analysis of extreme weather events and their response to the climate change and climate variability trend. Contributions on model simulations and evaluations to advance the understanding of physics and dynamics associated with climate-change-related weather hazards will also be considered. Submissions in, but not limited to, the following research areas are invited:

Climate change;
Climate variability;
Extreme events;
Climate modeling;
Hydroclimate;
Hydrometeorology.

Dr. Sridhara Nayak
Dr. Netrananda Sahu
Guest Editors

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Keywords

  • climate change
  • climate variability
  • extreme events
  • climate modeling
  • hydroclimate 
  • hydrometeorology

Published Papers (17 papers)

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Research

32 pages, 15617 KiB  
Article
Trends and Variability in Temperature and Related Extreme Indices in Rwanda during the Past Four Decades
by Bonfils Safari and Joseph Ndakize Sebaziga
Atmosphere 2023, 14(9), 1449; https://doi.org/10.3390/atmos14091449 - 17 Sep 2023
Viewed by 1231
Abstract
Analysis of the trends and variability of climate variables and extreme climate events is important for climate change detection in space and time. In this study, the trends and variabilities of minimum, maximum, and mean temperatures, as well as five extreme temperature indices, [...] Read more.
Analysis of the trends and variability of climate variables and extreme climate events is important for climate change detection in space and time. In this study, the trends and variabilities of minimum, maximum, and mean temperatures, as well as five extreme temperature indices, are analyzed over Rwanda for the period of 1983 to 2022. The Modified Mann–Kendall test and the Theil–Sen estimator are used for the analysis of, respectively, the trend and the slope. The standard deviation is used for the analysis of the temporal variability. It is found, on average, over the country, a statistically significant (α = 0.05) positive trend of 0.17 °C/decade and 0.20 °C/decade in minimum temperature, respectively, for the long dry season and short rain season. Statistically significant (α = 0.05) positive trends are observed for spatially averaged cold days (0.84 days/decade), warm nights (0.62 days/decade), and warm days (1.28 days/decade). In general, maximum temperature represents higher variability compared to the minimum temperature. In all seasons except the long dry season, statistically significant (α = 0.05) high standard deviations (1.4–1.6 °C) are observed over the eastern and north-western highlands for the maximum temperature. Cold nights show more variability, with a standard deviation ranging between 5 and 7 days, than the cold days, warm nights, and warm days, having, respectively, standard deviations ranging between 2 and 3, 4 and 5 days, and 3 and 4, and, especially in the area covering the central, south-western, south-central, and northwestern parts of Rwanda. Temperature increase and its variability have an impact on agriculture, health, water resources, infrastructure, and energy. The results obtained from this study are important since they can serve as the baseline for future projections. These can help policy decision making take objective measures for mitigation and adaptation to climate change impacts. Full article
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17 pages, 6070 KiB  
Article
Changes to Sea Surface Temperatures and Vertical Wind Shear and Their Influence on Tropical Cyclone Activity in the Caribbean and the Main Developing Region
by Keneshia Hibbert, Equisha Glenn, Thomas M. Smith and Jorge E. González-Cruz
Atmosphere 2023, 14(6), 999; https://doi.org/10.3390/atmos14060999 - 09 Jun 2023
Cited by 1 | Viewed by 2291
Abstract
Sea surface temperatures and vertical wind shear are essential to tropical cyclone formation. TCs need warm SSTs and low shear for genesis. Increasing SSTs and decreasing VWS influences storm development. This work analyzes SST and VWS trends for the Caribbean, surrounding region, and [...] Read more.
Sea surface temperatures and vertical wind shear are essential to tropical cyclone formation. TCs need warm SSTs and low shear for genesis. Increasing SSTs and decreasing VWS influences storm development. This work analyzes SST and VWS trends for the Caribbean, surrounding region, and the Atlantic hurricane main developing region from 1982–2020. Storm intensity increases significantly during this period. Annual and seasonal trends show that regional SSTs in the MDR are warming annually at 0.0219 °C yr−1 and, per season, 0.0280 °C yr−1. Simultaneously, VWS decreases during the late rainfall season, at 0.056 m/s yr−1 in the MDR and 0.0167 m/s yr−1 in the Caribbean and surrounding area. The Atlantic Warm Pool is expanding at 0.51 km2 per decade, increasing upper atmospheric winds and driving VWS changes. Correlations of large-area averages do not show significant relationships between TC intensity, frequency, and SSTs/VWS during the LRS. The observed changes appear to be associated with regional warming SSTs impacting TC changes. Plain Language Abstract: Tropical cyclone (TC) formation requires warm ocean waters and low wind shear. Changes to sea surface anomalies and wind shear influences are essential to understanding storm development and intensification. The ability to forecast storm changes is vital to human lives and livelihoods. This work analyzes sea surface temperatures (SSTs) and vertical wind shear (VWS) trends in the Caribbean, surrounding areas, and the Atlantic main developing region (MDR). We found increasing SSTs, decreasing wind shears, an expanding Atlantic Warm Pool (AWP), and increased storm intensity during the Atlantic hurricane season. Full article
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19 pages, 4800 KiB  
Article
The Effects of Drought in the Huaibei Plain of China Due to Climate Change
by Ousmane Badji, Yonghua Zhu, Haishen Lü, Kanon Guédet Guédé, Tingxing Chen, Abdoulaye Oumarou, Kouassi Bienvenue Mikael Onan Yao and Sika Brice
Atmosphere 2023, 14(5), 860; https://doi.org/10.3390/atmos14050860 - 11 May 2023
Viewed by 1186
Abstract
Damage from climate change is widespread throughout the world. This change has brought about calamities, the most prevalent of which is the emergence of numerous droughts which are increasingly threatening human lives. In this paper, we studied the spatial and temporal variations of [...] Read more.
Damage from climate change is widespread throughout the world. This change has brought about calamities, the most prevalent of which is the emergence of numerous droughts which are increasingly threatening human lives. In this paper, we studied the spatial and temporal variations of drought under the effect of climate change in the Huaibei Plain, which is a very important agricultural zone in China. Drought has attracted increasing attention in research due to its heavy impact on agriculture, the environment, livelihood, and food security. The SPEI (Standardized Precipitation Evapotranspiration Index) has been used in this study to express and identify drought events in the Huaibei Plain due to climate change. A general circulation model (GCM), HadGEM2-AO, which was the most appropriate for the study area’s precipitation simulation, and three Representative Concentration Pathways (RCP), RCP 2.6, RCP 4.5, and RCP 8.5, were used to analyze and compare the drought effect for the baseline (1985–2017) and the future climate scenarios (2025–2090). At 3 and 6 months, the SPEI successfully detects agricultural drought in temporal and spatial variation. However, according to the analysis, more severe agricultural drought events are foreseen in the future than in the baseline because of climate change. SPEI performed better than SPI in detecting drought in the baseline and simulated data due to increased evapotranspiration. Between the SPEI-3 and SPEI-6, the Pearson coefficient correlation reveals a positive association. The Mann-Kendall test was used to cover the two studied periods in order to establish the drought trend. Both decreasing and increasing trends, in different timescales, were detected by Sen’s Slope in the baseline and future periods with all RCPs. Full article
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19 pages, 10168 KiB  
Article
Decomposing Fast and Slow Responses of Global Cloud Cover to Quadrupled CO2 Forcing in CMIP6 Models
by Xixun Zhou, Hua Zhang, Qiuyan Wang and Bing Xie
Atmosphere 2023, 14(4), 653; https://doi.org/10.3390/atmos14040653 - 30 Mar 2023
Viewed by 1400
Abstract
Cloud changes and their attribution under global warming still remains a challenge in climatic change studies, especially in decomposing the fast and slow cloud responses to anthropogenic forcing. In this study, the responses of global cloud cover to the quadrupled CO2 forcing [...] Read more.
Cloud changes and their attribution under global warming still remains a challenge in climatic change studies, especially in decomposing the fast and slow cloud responses to anthropogenic forcing. In this study, the responses of global cloud cover to the quadrupled CO2 forcing are investigated quantitatively by decomposing the total response into fast and slow ones using the multi-model data from the Coupled Model Intercomparison Project Phase 6 (CMIP6). During the quasi-equilibrium period after the quadrupling of CO2 forcing, the global mean changes of simulated total cloud cover (TCC) in the total, fast, and slow responses are −2.42%, −0.64%, and −1.78%, respectively. Overall, the slow response dominates the total response in most regions over the globe with similar spatial patterns. TCC decreases at middle and low latitudes but increases at high latitudes in the total and slow responses. Whereas, it mainly decreases in the middle and low latitudes of the southern hemisphere as well as in the middle and high latitudes of the northern hemisphere in the fast response. A change in vertical motion is the major contributor to the cloud cover change at middle and low latitudes, while the decrease in upper atmospheric temperature leads to an increase in high cloud cover at high latitudes. In addition, the anomaly in water vapor convergence/diffusion also contributes to the cloud cover increase/decrease at low latitudes. Full article
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17 pages, 4444 KiB  
Article
Prediction of Extremely Severe Cyclonic Storm “Fani” Using Moving Nested Domain
by Kuvar Satya Singh, Sridhara Nayak, Suman Maity, Hara Prasad Nayak and Soma Dutta
Atmosphere 2023, 14(4), 637; https://doi.org/10.3390/atmos14040637 - 28 Mar 2023
Cited by 1 | Viewed by 1567
Abstract
The prediction of extremely severe cyclonic storms has been a long-standing and challenging issue due to their short life period and large variation in intensities over a short time. In this study, we predict the track, intensity, and structure of an extremely severe [...] Read more.
The prediction of extremely severe cyclonic storms has been a long-standing and challenging issue due to their short life period and large variation in intensities over a short time. In this study, we predict the track, intensity, and structure of an extremely severe cyclonic storm (ESCS) named ‘Fani,’ which developed over the Bay of Bengal region from 27 April to 4 May 2019, using the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) model. Two numerical experiments were conducted using the moving nested domain method with a 3 km horizontal resolution, one with the FLUX-1 air-sea flux parameterization scheme and the other with the FLUX-2 air-sea flux parameterization scheme. The NCEP operational Global Forecast System (GFS) analysis and forecast datasets with a 25 km horizontal resolution were used to derive the initial and boundary conditions. The WRF model’s predicted track and intensity were validated with the best-fit track dataset from the India Meteorological Department (IMD), and the structure was validated with different observations. The results showed that the WRF model with the FLUX-1 air-sea parameterization scheme accurately predicted the track, landfall (position and time), and intensity (minimum sea level pressure and maximum surface wind) of the storm. The track errors on days 1 to 4 were approximately 47 km, 123 km, 96 km, and 27 km in the FLUX-1 experiment and approximately 54 km, 142 km, 152 km, and 166 km in the FLUX-2 experiment, respectively. The intensity was better predicted in the FLUX-1 experiment during the first 60 h, while it was better predicted in the FLUX-2 experiment for the remaining period. The structure, in terms of relative humidity, water vapor, maximum reflectivity, and temperature anomaly of the storm, was also discussed and compared with available satellite and Doppler Weather Radar observations. Full article
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18 pages, 14282 KiB  
Article
Effects of Wave-Mean Flow Interaction on the Multi-Time-Scale Variability of the AO Indices: A Case Study of Winters 2007/08 and 2009/10
by Sujie Liang, Yanju Liu and Yihui Ding
Atmosphere 2023, 14(3), 524; https://doi.org/10.3390/atmos14030524 - 09 Mar 2023
Cited by 1 | Viewed by 1686
Abstract
Wave-mean flow interaction is usually regarded as accounting for the origin of the Arctic Oscillation/Northern Hemisphere Annular Mode (AO/NAM). It is inferred that the combination of the local wave-mean flow interactions at the AO/NAM’s three regional centers of action on three important time [...] Read more.
Wave-mean flow interaction is usually regarded as accounting for the origin of the Arctic Oscillation/Northern Hemisphere Annular Mode (AO/NAM). It is inferred that the combination of the local wave-mean flow interactions at the AO/NAM’s three regional centers of action on three important time scales contributes to the main behavior of the AO/NAM index. To discuss the variations of the AO/NAM indices on the three prominent time scales, we take the 2007/08 and 2009/10 winters as two comparative examples to analyze the local wave-mean flow interactions at the AO/NAM’s three centers. The following three facets are identified: (1) Synoptic-scale wave breakings in the North Atlantic can explain the variances of the AO/NAM index on a time scale of 10–20 days. In the 2007/08 winter, there were both cyclonic and anticyclonic synoptic wave breakings, while in the 2009/10 winter, cyclonic synoptic wave breaking was dominant, and the flow characteristics were strikingly similar to the blocking. (2) In the 2007/08 and 2009/10 winters, the signals of the AO/NAM indices on the time scale of 30–60 days are mainly from the interactions between the upward propagating quasi-stationary waves and the polar vortex in the stratosphere. (3) This work also demonstrates that the AO/NAM is linked to the El Niño–Southern Oscillation (ENSO) by the Pacific–North American pattern (PNA) on the winter mean time scale. In the 2007/08 (2009/10) winter, La Niña (El Niño) forced the Pacific jet to shift poleward (equatorward), in favor of weakening (enhancing) the polar waveguide; thus, the polar vortex became stronger (weaker), corresponding to the positive (negative) winter mean AO/NAM index. Full article
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9 pages, 2234 KiB  
Communication
Mid-Latitude Jet Response to Pan-Arctic and Regional Arctic Warming in Idealized GCM
by Gun-Hwan Yang, Woosok Moon, Hayeon Noh and Baek-Min Kim
Atmosphere 2023, 14(3), 510; https://doi.org/10.3390/atmos14030510 - 06 Mar 2023
Viewed by 1214
Abstract
To study the dynamical mechanism by which Arctic amplification affects extreme weather events in mid-latitude, we investigated the local and remote circulation response to pan-Arctic and regional Arctic thermal forcing. A comprehensive atmospheric GCM (General Circulation Model) coupled to a slab mixed-layer ocean [...] Read more.
To study the dynamical mechanism by which Arctic amplification affects extreme weather events in mid-latitude, we investigated the local and remote circulation response to pan-Arctic and regional Arctic thermal forcing. A comprehensive atmospheric GCM (General Circulation Model) coupled to a slab mixed-layer ocean model is used for the experiment. With the increasing thermal forcing in the pan-Arctic configuration, the mid-latitude jet tends to shift equatorward, mainly due to the southward shift of the convergence zone of eddy-heat flux and eddy-momentum flux. From the regional Arctic forced experiments, zonal mean response is similar to the response from the pan-Arctic configuration. The non-zonal response is characterized by the 300 hPa circumpolar zonal wind of wavenumber-1 structure, which establishes an enhanced wavier mid-latitude jet. In the polar region at 300 hPa, regional thermal forcing drives a distinct east–west dipole circulation pattern, in which anticyclonic circulation is located to the west of the thermal forcing, and cyclonic circulation is located to the east. The lower-level circulation shows the opposite pattern to the upper-level circulation in the polar region. While the strength of circulation increases with gradual thermal forcing, the overall dipole pattern is unchanged. In regional warming simulation, compared to the pan-Arctic warming, increasing residual heat flux in a dipole pattern causes enhanced heat advection to mid-latitude. Full article
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23 pages, 5306 KiB  
Article
A Climatological and Synoptic Analysis of Winter Cold Spells over the Balkan Peninsula
by Efstathia Tringa, Konstantia Tolika, Christina Anagnostopoulou and Effie Kostopoulou
Atmosphere 2022, 13(11), 1851; https://doi.org/10.3390/atmos13111851 - 07 Nov 2022
Cited by 2 | Viewed by 1492
Abstract
An extensive climatological and synoptic analysis of the winter cold spells that occurred in the Balkan Peninsula over a 59-year study period (1961–2019) is the aim of the present study. Winter cold spells (WCSPs hereafter) are defined as periods of at least three [...] Read more.
An extensive climatological and synoptic analysis of the winter cold spells that occurred in the Balkan Peninsula over a 59-year study period (1961–2019) is the aim of the present study. Winter cold spells (WCSPs hereafter) are defined as periods of at least three consecutive days when the daily minimum temperature is below the 5% of the empirical winter distributions. This diagnostic index is used to detect the occurrence of cold events during the study period, while the duration, frequency, and intensity of these extreme climate events are further analyzed. Moreover, in order to investigate the relation of the WCSPs with the atmospheric circulation, two daily circulation type calendars, derived from an advanced automatic flexible classification, were utilized. The automatic daily circulation type calendars were used, aiming at identifying the atmospheric conditions that prevail before or during WCSPs. The climatological analysis showed that the spatial distribution of the extreme minimum temperatures in the Balkan Peninsula presents a positive gradient from north to south, whereas coastal areas present more moderate minimum temperatures than inland areas of the region. In terms of WCSPs, the winter of 1962–1963 was the one with the longest WCSPs, for most of the stations under study. In general, a decreasing trend in the frequency of WCSP occurrence has been found towards the end of the study period. The circulation type investigation revealed that, during WCSPs in the Balkan region, the associated circulation at the 500 hPa is the Cne (cyclonic northeastern) and at the 1000 hPa is the Anw (anticyclonic northwest). Full article
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12 pages, 6981 KiB  
Article
Grain-Size End-Members of Anguli-Nuur Lake Core Sediments: Evidence for Moisture Variability in Northern China since the Last Deglaciation
by Junfeng Li, Xingqi Liu, Xin Mao and Huiqing Yang
Atmosphere 2022, 13(11), 1826; https://doi.org/10.3390/atmos13111826 - 02 Nov 2022
Viewed by 1488
Abstract
The common methods used for grain-size analysis have their own deficiencies and limitations in terms of explaining the genesis of grain-size components. In this study, the end-member modeling analysis method is applied to multi-mode grain-size distributions of core sediment from Anguli-nuur lake to [...] Read more.
The common methods used for grain-size analysis have their own deficiencies and limitations in terms of explaining the genesis of grain-size components. In this study, the end-member modeling analysis method is applied to multi-mode grain-size distributions of core sediment from Anguli-nuur lake to help to understand the sediment provenance, transport processes and sedimentary environment. Four optimal end-members are unmixed, and three transport-deposition processes are revealed, including the runoff, wave and aeolian processes. The humidity index synthesized by the runoff and aeolian end-members in the core sediment is used to reconstruct the humidity variability in the East Asian monsoonal domain since the last deglaciation. Our record shows that the patterns of humidity variability are coincidentally linked with the monsoonal precipitation index from the same core and stalagmite record in southern China. The Holocene optimum is identified in early and middle Holocene. In addition, a series of millennial- and multi-centennial-scale dry events documented in our record are well correlated with the ice-rafted debris events in the North Atlantic. The results reveal that the grain-size record from Anguli-nuur lake is sensitive in response to moisture variability in northern China. Full article
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13 pages, 4160 KiB  
Article
The Spatio-Temporal Onset Characteristics of Indian Summer Monsoon Rainfall and Their Relationship with Climate Indices
by Atul Saini, Netrananda Sahu, Saroj K. Mishra, Shipra Jain, Swadhin Behera and Sushil K. Dash
Atmosphere 2022, 13(10), 1581; https://doi.org/10.3390/atmos13101581 - 28 Sep 2022
Cited by 3 | Viewed by 2589
Abstract
Regional variations of monsoon onset dates across India were analyzed for 67 years (1951–2017) under different modes of climate variations, i.e., El Niño, La Niña, and the Indian Ocean Dipole (IOD), along with flood and drought years using the objective method and statistical [...] Read more.
Regional variations of monsoon onset dates across India were analyzed for 67 years (1951–2017) under different modes of climate variations, i.e., El Niño, La Niña, and the Indian Ocean Dipole (IOD), along with flood and drought years using the objective method and statistical techniques. Monsoon onset analysis revealed that the northern, northeastern, and southern parts were highly susceptible to the early onset of La Niña, and the northern and northern northwest parts were highly susceptible to the early onset of El Niño. The onset dates were early (late) in the sub-regions of the central, southern, and northeastern (northern, northwestern, and western) parts of India during flood (drought) years. Further, onset dates in flood years occurred earlier than those in La Niña years, and onset dates in drought years were later than those in El Niño years. The onset occurrence probability and influence of the synoptic events are discussed. This research could help in understanding the onset of monsoon and its predictability for societal applications. Full article
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14 pages, 4905 KiB  
Article
The Impact of El-Niño and La-Niña on the Pre-Monsoon Convective Systems over Eastern India
by Rajesh Kumar Sahu, Goutam Choudhury, Naresh Krishna Vissa, Bhishma Tyagi and Sridhara Nayak
Atmosphere 2022, 13(8), 1261; https://doi.org/10.3390/atmos13081261 - 09 Aug 2022
Cited by 2 | Viewed by 2180
Abstract
El-Niño and La-Niña are believed to change the intensity and frequencies of extreme weather events globally. The present study aims to analyse the impact of El-Niño and La-Niña on the lightning activities of cloud systems and their associated precipitation and thermodynamic indices over [...] Read more.
El-Niño and La-Niña are believed to change the intensity and frequencies of extreme weather events globally. The present study aims to analyse the impact of El-Niño and La-Niña on the lightning activities of cloud systems and their associated precipitation and thermodynamic indices over the Eastern India regions (Odisha, Jharkhand, and West Bengal) during the pre-monsoon season (March–May). Eastern India receives catastrophic thunderstorm events during the pre-monsoon season. The results suggest that the number of lightning flashes was higher in the El-Niño years than in the La-Niña periods, which helps convective activities to be developed over the study region. The precipitation variations showed similar patterns during El-Niño and La-Niña periods, but the magnitudes were higher in the latter. Results from the analysis of thermodynamic indices show that, during the La-Niña phase, the convective available potential energy (CAPE), convective inhibition (CIN), severe weather threat index (SWEAT), humidity index (HI), and total totals index (TTI) values increased, while the cross total index (CTI) and K index (KI) decreased. In contrast, the vertical total index (VTI) and Boyden index (BI) values showed less significant changes in both El-Niño and La-Niña periods. The anomalies of flash rate densities over most parts of our domain were positive during the El-Niño years and negative during the La-Niña years. Precipitation anomalies had a higher positive magnitude during the La-Niña phase, but had spatial variability similar to the El-Niño phase. The anomalies of most of the thermodynamic indices also showed noticeable differences between El-Niño and La-Niña periods, except for the HI index. El-Niño periods showed higher lightning and increased values of associated thermodynamic indices over eastern India, indicating more pronounced convective systems. Full article
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21 pages, 3195 KiB  
Article
Seasonal Climate Trends across the Wild Blueberry Barrens of Maine, USA
by Rafa Tasnim, Sean Birkel, Lily Calderwood, Samuel Roberts and Yong-Jiang Zhang
Atmosphere 2022, 13(5), 690; https://doi.org/10.3390/atmos13050690 - 26 Apr 2022
Viewed by 2249
Abstract
Wild blueberries in Maine, USA are facing threats from our changing climate. While summer climate variations have been affecting this important commercial crop directly, significant climate variations in other seasons also can be potentially detrimental to blueberry production. Therefore, we analyzed annual and [...] Read more.
Wild blueberries in Maine, USA are facing threats from our changing climate. While summer climate variations have been affecting this important commercial crop directly, significant climate variations in other seasons also can be potentially detrimental to blueberry production. Therefore, we analyzed annual and seasonal climate trends (temperature, rainfall, snow cover) over the past 41 years (1980–2020) for seven Maine counties (Piscataquis, Washington, Hancock, Knox, Lincoln, Kennebec, York) with large wild blueberry areas. We found that, across all blueberry production fields (or “barrens”), historical temperatures increased significantly (p < 0.05) in the fall and winter followed by summer, but not in the spring. Additionally, precipitation increased slightly (0.5–1.2 mm/year) in the winter and fall, whereas no changes were found in the spring and summer. Furthermore, we found that historical temperatures were lower in Piscataquis (north-central) and Washington (north-east) counties, whereas in south-western counties (Hancock to York) experienced a relatively warmer climate. The rate of increasing temperature was comparatively slower in the warmer barrens located towards the south-west (Hancock to York). Moreover, the growing season lengthened towards the fall season consistently in all locations, whereas lengthening towards the spring was inconsistent. These findings inform the wild blueberry growers in different locations of Maine about the seasonal shifts occurring for their crop. This knowledge may assist with land management planning in order for the growers to prepare for future impacts. Full article
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15 pages, 4465 KiB  
Article
The Effect of Anthropogenic Heat and Moisture on Local Weather at Industrial Heat Islands: A Numerical Experiment
by Parthasarathi Mishra, Srinivasa Ramanujam Kannan and Chandrasekar Radhakrishnan
Atmosphere 2022, 13(2), 357; https://doi.org/10.3390/atmos13020357 - 20 Feb 2022
Cited by 6 | Viewed by 1708
Abstract
The current study addresses the role of heat and moisture emitted from anthropogenic sources on the local weather with the aid of numerical weather prediction (NWP). The heat and moisture emitted by industries to the atmosphere are considered main sources in this study. [...] Read more.
The current study addresses the role of heat and moisture emitted from anthropogenic sources on the local weather with the aid of numerical weather prediction (NWP). The heat and moisture emitted by industries to the atmosphere are considered main sources in this study. In order to understand the effect of heat and moisture on local weather, the study is conducted to capture the impact of heat with no moisture change. The results are compared against a control run case without perturbation and also against the case where both heat and moisture are perturbed with temperature as a single parameter. The Angul district in Odisha that houses over 4000 industries is considered our study region. The numerical simulations are performed using the mesoscale Weather Research and Forecasting (WRF) model for two rain events, namely a light rain case and a heavy rain case, with different physics options available in the WRF model. The WRF simulated maximum rainfall rate using various microphysics schemes are compared with the Tropical rainfall measuring mission (TRMM) observations for validation purposes. Our study shows that the WDM6 double moment microphysics scheme is better in capturing rain events. The TRMM-validated WRF simulation is considered a reference state of the atmosphere against which comparisons for the perturbed case are made. The surface temperature is perturbed by increasing it by 10 K near the industrial site and exponentially decreasing it with height up to the atmospheric boundary layer. A numerical experiment represents heating without addition of moisture by recalculating the relative humidity (RH) corresponding to the perturbed temperature. The perturbed temperature affects sensible heat (SH) and latent heat (LH) parameters in the numerical experiment. From the results of the numerical investigation, it is found that the near-surface rainfall rate increases locally in a reasonable manner with the addition of sensible heat to the atmosphere. A comparison against the case where moisture is added shows that enhanced rainfall is more sensitive to sensible and latent heat than sensible heat alone. Full article
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15 pages, 6916 KiB  
Article
Variation in Extreme Temperature and Its Instability in China
by Hongju Chen, Jianping Yang, Yongjian Ding, Chunping Tan, Qingshan He, Yanxia Wang, Ji Qin, Fan Tang and Qiuling Ge
Atmosphere 2022, 13(1), 19; https://doi.org/10.3390/atmos13010019 - 23 Dec 2021
Cited by 4 | Viewed by 2394
Abstract
In this study, the instability of extreme temperatures is defined as the degree of perturbation of the spatial and temporal distribution of extreme temperatures, which is to show the uncertainty of the intensity and occurrence of extreme temperatures in China. Based on identifying [...] Read more.
In this study, the instability of extreme temperatures is defined as the degree of perturbation of the spatial and temporal distribution of extreme temperatures, which is to show the uncertainty of the intensity and occurrence of extreme temperatures in China. Based on identifying the extreme temperatures and by analyzing their variability, we refer to the entropy value in the entropy weight method to study the instability of extreme temperatures. The results show that TXx (annual maximum value of daily maximum temperature) and TNn (annual minimum value of daily minimum temperature) in China increased at 0.18 °C/10 year and 0.52 °C/10 year, respectively, from 1966 to 2015. The interannual data of TXx’ occurrence (CTXx) and TNn’ occurrence (CTNn), which are used to identify the timing of extreme temperatures, advance at 0.538 d/10 year and 1.02 d/10 year, respectively. In summary, extreme low-temperature changes are more sensitive to global warming. The results of extreme temperature instability show that the relative instability region of TXx is located in the middle and lower reaches of the Yangtze River basin, and the relative instability region of TNn is concentrated in the Yangtze River, Yellow River, Langtang River source area and parts of Tibet. The relative instability region of CTXx instability is distributed between 105° E and 120° E south of the 30° N latitude line, while the distribution of CTNn instability region is more scattered; the TXx’s instability intensity is higher than TNn’s, and CTXx’s instability intensity is higher than CTNn’s. We further investigate the factors affecting extreme climate instability. We also find that the increase in mean temperature and the change in the intensity of the El Niño phenomenon has significant effects on extreme temperature instability. Full article
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18 pages, 8663 KiB  
Article
A Contrast of Recent Changing Tendencies in Genesis Productivity of Tropical Cloud Clusters over the Western North Pacific in May and October
by Xugang Peng, Lei Wang, Minmin Wu and Qiuying Gan
Atmosphere 2021, 12(9), 1177; https://doi.org/10.3390/atmos12091177 - 13 Sep 2021
Cited by 6 | Viewed by 1636
Abstract
Tropical cloud clusters (TCCs) are embryos of tropical cyclones (TCs) and may have the potential to develop into TCs. The genesis productivity (GP) of TCCs is used to quantify the proportion of TCCs that can evolve into TCs. Recent studies have revealed a [...] Read more.
Tropical cloud clusters (TCCs) are embryos of tropical cyclones (TCs) and may have the potential to develop into TCs. The genesis productivity (GP) of TCCs is used to quantify the proportion of TCCs that can evolve into TCs. Recent studies have revealed a decrease in GP of western North Pacific (WNP) TCCs during the extended boreal summer (July–October) since 1998. Here, we show that the changing tendencies in GP of WNP TCCs have obvious seasonality. Although most months could see recent decreases in GP of WNP TCCs, with October experiencing the strongest decreasing trend, May is the only month with a significant recent increasing trend. The opposite changing tendencies in May and October could be attributed to different changes in low-level atmospheric circulation anomalies triggered by different sea surface temperature (SST) configurations across the tropical oceans. In May, stronger SST warming in the tropical western Pacific could prompt increased anomalous westerlies associated with anomalous cyclonic circulation, accompanied by the weakening of the WNP subtropical high and the strengthening of the WNP monsoon. Such changes in background atmospheric circulations could favor the enhancement of atmospheric eddy kinetic energy and barotropic energy conversions, resulting in a recent intensified GP of WNP TCCs in May. In October, stronger SST warming in the tropical Atlantic and Indian Oceans contributed to anomalous easterlies over the tropical WNP associated with anomalous anticyclonic circulation, giving rise to the suppressed atmospheric eddy kinetic energy and recent weakened GP of WNP TCCs. These results highlight the seasonality in recent changing tendencies in the GP of WNP TCCs and associated large-scale atmospheric-oceanic conditions. Full article
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28 pages, 8142 KiB  
Article
Impact of Soil Moisture Initialization in the Simulation of Indian Summer Monsoon Using RegCM4
by Suman Maity, Sridhara Nayak, Kuvar Satya Singh, Hara Prasad Nayak and Soma Dutta
Atmosphere 2021, 12(9), 1148; https://doi.org/10.3390/atmos12091148 - 05 Sep 2021
Cited by 4 | Viewed by 2222
Abstract
Soil moisture is one of the key components of land surface processes and a potential source of atmospheric predictability that has received little attention in regional scale studies. In this study, an attempt was made to investigate the impact of soil moisture on [...] Read more.
Soil moisture is one of the key components of land surface processes and a potential source of atmospheric predictability that has received little attention in regional scale studies. In this study, an attempt was made to investigate the impact of soil moisture on Indian summer monsoon simulation using a regional model. We conducted seasonal simulations using a regional climate model (RegCM4) for two different years, viz., 2002 (deficit) and 2011 (normal). The model was forced to initialize with the high-resolution satellite-derived soil moisture data obtained from the Climate Change Initiative (CCI) of the European Space Agency (ESA) by replacing the default static soil moisture. Simulated results were validated against high-resolution surface temperature and rainfall analysis datasets from the India Meteorology Department (IMD). Careful examination revealed significant advancement in the RegCM4 simulation when initialized with soil moisture data from ESA-CCI despite having regional biases. In general, the model exhibited slightly higher soil moisture than observation, RegCM4 with ESA setup showed lower soil moisture than the default one. Model ability was relatively better in capturing surface temperature distribution when initialized with high-resolution soil moisture data. Rainfall biases over India and homogeneous regions were significantly improved with the use of ESA-CCI soil moisture data. Several statistical measures such as temporal correlation, standard deviation, equitable threat score (ETS), etc. were also employed for the assessment. ETS values were found to be better in 2011 and higher in the simulation with the ESA setup. However, RegCM4 was still unable to enhance its ability in simulating temporal variation of rainfall adequately. Although initializing with the soil moisture data from the satellite performed relatively better in a normal monsoon year (2011) but had limitations in simulating different epochs of monsoon in an extreme year (2002). Thus, the study concluded that the simulation of the Indian summer monsoon was improved by using RegCM4 initialized with high-resolution satellite soil moisture data although having limitations in predicting temporal variability. The study suggests that soil moisture initialization has a critical impact on the accurate prediction of atmospheric circulation processes and convective rainfall activity. Full article
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16 pages, 6159 KiB  
Article
Future Projections and Uncertainty Assessment of Precipitation Extremes in Iran from the CMIP6 Ensemble
by Juyoung Hong, Khadijeh Javan, Yonggwan Shin and Jeong-Soo Park
Atmosphere 2021, 12(8), 1052; https://doi.org/10.3390/atmos12081052 - 16 Aug 2021
Cited by 8 | Viewed by 2675
Abstract
Scientists who want to know future climate can use multimodel ensemble (MME) methods that combine projections from individual simulation models. To predict the future changes of extreme rainfall in Iran, we examined the observations and 24 models of the Coupled Model Inter-Comparison Project [...] Read more.
Scientists who want to know future climate can use multimodel ensemble (MME) methods that combine projections from individual simulation models. To predict the future changes of extreme rainfall in Iran, we examined the observations and 24 models of the Coupled Model Inter-Comparison Project Phase 6 (CMIP6) over the Middle East. We applied generalized extreme value (GEV) distribution to series of annual maximum daily precipitation (AMP1) data obtained from both of models and the observations. We also employed multivariate bias-correction under three shared socioeconomic pathway (SSP) scenarios (namely, SSP2-4.5, SSP3-7.0, and SSP5-8.5). We used a model averaging method that takes both performance and independence of model into account, which is called PI-weighting. Return levels for 20 and 50 years, as well as the return periods of the AMP1 relative to the reference years (1971–2014), were estimated for three future periods. These are period 1 (2021–2050), period 2 (2046–2075), and period 3 (2071–2100). From this study, we predict that over Iran the relative increases of 20-year return level of the AMP1 in the spatial median from the past observations to the year 2100 will be approximately 15.6% in the SSP2-4.5, 23.2% in the SSP3-7.0, and 28.7% in the SSP5-8.5 scenarios, respectively. We also realized that a 1-in-20 year (or 1-in-50 year) AMP1 observed in the reference years in Iran will likely become a 1-in-12 (1-in-26) year, a 1-in-10 (1-in-22) year, and a 1-in-9 (1-in-20) year event by 2100 under the SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, respectively. We project that heavy rainfall will be more prominent in the western and southwestern parts of Iran. Full article
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