scholarly journals Variability and trends of climate extremes indices from the observed and downscaled GCMs data over 1950–2020 period in Chattogram City, Bangladesh

2021 ◽  
Author(s):  
Lia Pervin ◽  
Sabbir Mostafa Khan
Keyword(s):  
Regional Climate ◽  
Climate Extremes ◽  
Climate Indices ◽  
Heat Map ◽  
Maximum Rainfall ◽  
The Sustainable Development ◽  
Slope Test ◽  
Daily Data ◽  
Increasing Trend ◽  
Map Analysis

Abstract This study was intended to evaluate the variability and trends of climate extremes by incorporating daily data from Chattogram station and from the high-resolution Coordinated Regional Climate Downscaling Experiment (CORDEX) for two different time series. Here, we also focused on evaluating the performance of the selected RCMs (CanESM2, CSIRO, and GFDL from CORDEX) using Taylor diagrams and heat map analysis. Twenty-two extreme climate indices from ETCCDI were computed for 1950–1989 and 1990–2020 periods. Mann–Kendall and Sen's slope test were performed to estimate the trends from the indices from both station and RCMs data. Highly significant increasing trend for the warm days and warm nights’ frequencies were found, whereas, the frequency of cold days and cold nights indicated significantly decreasing trend. On the other hand, mild increasing trend in 1-day and 5-day maximum rainfall was detected. Also, the average annual precipitation has increased by 6% from the 1950–1989 to 1990–2020 period. During the last three decades, the region has experienced more heavier rainfall in the monsoon but increased water stress in the dry season. The two-fold effects of climate change on the local hydrology revealed by this study need to be addressed properly for the sustainable development of this region.

scholarly journals Multidecadal Evaluation of WRF Downscaling Capabilities over Western Australia in Simulating Rainfall and Temperature Extremes

2015 ◽  
Vol 54 (2) ◽  
pp. 370-394 ◽  
Author(s):  
Julia Andrys ◽  
Thomas J. Lyons ◽  
Jatin Kala
Keyword(s):  
High Resolution ◽  
Western Australia ◽  
General Circulation ◽  
Regional Climate ◽  
Wrf Model ◽  
Climate Extremes ◽  
Convective Precipitation ◽  
Climate Simulation ◽  
Climate Indices ◽  
Climate Simulations

AbstractThe authors evaluate a 30-yr (1981–2010) Weather Research and Forecast (WRF) Model regional climate simulation over the southwest of Western Australia (SWWA), a region with a Mediterranean climate, using ERA-Interim boundary conditions. The analysis assesses the spatial and temporal characteristics of climate extremes, using a selection of climate indices, with an emphasis on metrics that are relevant for forestry and agricultural applications. Two nested domains at 10- and 5-km resolution are examined, with the higher-resolution simulation resolving convection explicitly. Simulation results are compared with a high-resolution, gridded observational dataset that provides daily rainfall, minimum temperatures, and maximum temperatures. Results show that, at both resolutions, the model is able to simulate the daily, seasonal, and annual variation of temperature and precipitation well, including extreme events. The higher-resolution domain displayed significant performance gains in simulating dry-season convective precipitation, rainfall around complex terrain, and the spatial distribution of frost conditions. The high-resolution domain was, however, influenced by grid-edge effects in the southwestern margin, which reduced the ability of the domain to represent frontal rainfall along the coastal region. On the basis of these results, the authors feel confident in using the WRF Model for regional climate simulations for the SWWA, including studies that focus on the spatial and temporal representation of climate extremes. This study provides a baseline climatological description at a high resolution that can be used for impact studies and will also provide a benchmark for climate simulations driven by general circulation models.

Climatic Trends and Impact on Agriculture in Ningxia

2012 ◽  
Vol 518-523 ◽  
pp. 5921-5930
Author(s):  
Hong Xiang Chen ◽  
Ya Ping Li
Keyword(s):  
Crop Yields ◽  
Regional Climate ◽  
Climate Impact ◽  
Plant Diseases ◽  
Maximum Temperature ◽  
Climate Indices ◽  
Average Temperature ◽  
Daily Data ◽  
Actual Use ◽  
Frost Free Period

This paper characterizes the climate characteristics and observed climate variability in Ningxia, China, using observed daily data from 15 meteorological stations. Climate indices until 2050 and 2100 are projected using the Regional climate impact models PRECIS (Providing Regional Climates for Impacts Studies), emphasizing those which are relevant to agriculture. The results show that the average temperature in Ningxia has increased from 1961-2010 while the mean precipitation has decreased. The frost-free period and accumulated temperature ≥0°C have also increased. Frost-free periods have increased and extended the growing season. PRECIS shows that the annual average temperature, minimum and maximum temperature is projected to increase. Annual precipitation will not change significantly, but the observed dry spells will continue. Increasing temperatures are beneficial for most crop yields but also increase the risk of plant diseases as planting and harvesting times have changed and will change. The regional disparity of water availability, demand and actual use will further be aggravated in future.

scholarly journals Climate Change Impact Assessment for Aji Basin Using Statistical Downscaling and Bias Correction of Climate Model Outputs

2016 ◽  
Vol 11 (2) ◽  
pp. 670-678 ◽  
Author(s):  
N. S Vithlani ◽  
H. D Rank
Keyword(s):  
Climate Change ◽  
Bias Correction ◽  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Regional Climate ◽  
Climate Extremes ◽  
Global Climate Models ◽  
Climate Indices ◽  
Climate Projections

For the future projections Global climate models (GCMs) enable development of climate projections and relate greenhouse gas forcing to future potential climate states. When focusing it on smaller scales it exhibit some limitations to overcome this problem, regional climate models (RCMs) and other downscaling methods have been developed. To ensure statistics of the downscaled output matched the corresponding statistics of the observed data, bias correction was used. Quantify future changes of climate extremes were analyzed, based on these downscaled data from two RCMs grid points. Subset of indices and models, results of bias corrected model output and raw for the present day climate were compared with observation, which demonstrated that bias correction is important for RCM outputs. Bias correction directed agreements of extreme climate indices for future climate it does not correct for lag inverse autocorrelation and fraction of wet and dry days. But, it was observed that adjusting both the biases in the mean and variability, relatively simple non-linear correction, leads to better reproduction of observed extreme daily and multi-daily precipitation amounts. Due to climate change temperature and precipitation will increased day by day.

scholarly journals Imputação Multivariada de Dados Diários de Precipitação e Análise de Índices de Extremos Climáticos (Imputation Multivariate of Precipitation Daily Data and Analysis of Climate Extremes Index)

2012 ◽  
Vol 5 (3) ◽  
pp. 661 ◽  
Author(s):  
Rafaela Lisboa Costa ◽  
Fabrício Daniel dos Santos Silva ◽  
Gabriel Fonseca Sarmanho ◽  
Paulo Sérgio Lucio
Keyword(s):  
Missing Values ◽  
Daily Rainfall ◽  
Climate Extremes ◽  
Climate Indices ◽  
Data Imputation ◽  
Climatic Trends ◽  
Daily Data ◽  
In Series ◽  
Grid Points ◽  
Source Of Information

Neste trabalho utilizou-se a técnica MICE (do inglês “Multivariate Imputation by Chained Equations”) para imputação de dados diários de precipitação em seis séries com falhas do Estado da Paraíba: Areia, Campina Grande, Monteiro, João Pessoa, Patos e São Gonçalo, entre período de 1979 e 2010, usando como fonte de informação para o preenchimento dados de pontos de grade próximos à estação meteorológica selecionada. Com a finalidade de validação do método, foram geradas falhas em dados observados para determinados anos - princípio da validação cruzada. A metodologia apresentou resultados promissores. Foram obtidos altos valores de correlações tanto entre os dados diários observados e imputados, assim como quando estes foram acumulados mensalmente. A partir dos dados imputados, utilizou-se o software R-ClimDex com o objetivo de avaliar possíveis tendências nos índices climáticos relacionados à precipitação. As análises das séries sem falhas mostraram que das cidades estudadas, Areia foi a única que apresentou tendência de redução no número de dias com chuvas acima de 1mm, enquanto as demais cidades apresentaram tendência de aumento.Palavras - chave: dados imputados, MICE, R-ClimDex, tendências climáticas. Imputation Multivariate of Precipitation Daily Data and Analysis of Climate Extremes Index ABSTRACTThis work used the MICE(Multivariate Imputation by Chained Equations) technique for daily rainfall data imputation in series with gaps, for six series of Paraiba State: Areia, Campina Grande, Monteiro, Joao Pessoa, Patos and São Gonçalo, between 1979 and 2010, using as a source of information data grid points near the selected station (nearest neighbors). In order to validate the method one generates missing values in observed data for certain years– the cross-validation principle. The methodology presented promising results. One obtains high values ​​for both correlations between daily observed and imputed data, as well as when they are monthly accumulates. Based on the imputed data, used the software R-ClimDex with the objective to evaluate possible trends in climate indices related to precipitation. The analysis of the series without flaws of the cities studied showed that Areia was the only one that showed decrease trend in the number of days with precipitation above1 mm, while the other cities showed increase trend.Keywords: imputed data, MICE, R-ClimDex, climatic trends.

scholarly journals Unpacking future climate extremes and their sectoral implications in western Nepal

2021 ◽  
Vol 168 (1-2) ◽  
Author(s):  
Dipesh Chapagain ◽  
Sanita Dhaubanjar ◽  
Luna Bharati
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Extreme Temperature ◽  
Climate Extremes ◽  
Climate Indices ◽  
Climate Projections ◽  
Temperature And Precipitation ◽  
Extreme Precipitation Events ◽  
The Impact ◽  
Precipitation Events

AbstractExisting climate projections and impact assessments in Nepal only consider a limited number of generic climate indices such as means. Few studies have explored climate extremes and their sectoral implications. This study evaluates future scenarios of extreme climate indices from the list of the Expert Team on Sector-specific Climate Indices (ET-SCI) and their sectoral implications in the Karnali Basin in western Nepal. First, future projections of 26 climate indices relevant to six climate-sensitive sectors in Karnali are made for the near (2021–2045), mid (2046–2070), and far (2071–2095) future for low- and high-emission scenarios (RCP4.5 and RCP8.5, respectively) using bias-corrected ensembles of 19 regional climate models from the COordinated Regional Downscaling EXperiment for South Asia (CORDEX-SA). Second, a qualitative analysis based on expert interviews and a literature review on the impact of the projected climate extremes on the climate-sensitive sectors is undertaken. Both the temperature and precipitation patterns are projected to deviate significantly from the historical reference already from the near future with increased occurrences of extreme events. Winter in the highlands is expected to become warmer and dryer. The hot and wet tropical summer in the lowlands will become hotter with longer warm spells and fewer cold days. Low-intensity precipitation events will decline, but the magnitude and frequency of extreme precipitation events will increase. The compounding effects of the increase in extreme temperature and precipitation events will have largely negative implications for the six climate-sensitive sectors considered here.

scholarly journals Temporal Analysis of Daily and 10 Minutes of Rainfall of Poprad Station in Eastern Slovakia

Hydrology ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 32 ◽  
Author(s):  
Adam Repel ◽  
Vinayakam Jothiprakash ◽  
Martina Zeleňáková ◽  
Helena Hlavatá ◽  
Ionut Minea
Keyword(s):  
Temporal Analysis ◽  
Descriptive Statistics ◽  
Annual Rainfall ◽  
Time Step ◽  
Total Rainfall ◽  
Maximum Rainfall ◽  
Daily Data ◽  
Increasing Trend ◽  
Daily Time Step ◽  
Daily Time

The aim of this paper is the application of temporal analysis of daily and 10 min of rainfall data from Poprad station, located in Eastern Slovakia. There are two types of data used in the analysis, firstly, a daily time step data, manually collected between the years 1951 and 2018 and secondly, 10 min of data, automatically collected between the years 2000 and 2018. For proper comparability, the automatically collected data has been recalculated to the daily form. After a comparison of the sets of data, manually collected daily data has been used in further analysis. The main analysis can be divided into two sections. The first section consists of basic statistics (mean, standard deviation, etc.) and the second section of descriptive statistics, where the subjects of examination were trend, stationarity, homogeneity, periodicity and noise. The results of the basic statistics outlined trend behavior in the data meaning that the annual total rainfall for the period 1951–2018 is slightly increasing but the further investigation supported by the methods of descriptive statistics refuted this thesis. The number of rainy days is decreasing but maximum rainfall intensity is increasing year by year, indicating that total rainfall is happening in lesser and lesser days, with an increase in the number of 0 rainfall days. The results demonstrated no presence of the trend or only a weak trend in daily time step, but a significant increasing trend in annual rainfall. Tests of stationarity proved that the data are stationary and, therefore, suitable for any hydrologic analysis. The tests of homogeneity showed no breakpoints in the data. The interesting result was demonstrated by the periodicity test, which showed exactly a 365.25 days’ period, while 0.25 indicates a leap year. As a summary for the Poprad station, there is no tendency of increasing of daily average rainfall, but slight increasing trend of total annual rainfall, the summer season has the highest ratio on total precipitation per year, September and October are the months with the highest numbers of days without rain.

scholarly journals Unpacking Future Climate Extremes and their Sectoral Implications in Western Nepal

2021 ◽  
Author(s):  
Dipesh Chapagain ◽  
Sanita Dhaubanjar ◽  
Luna Bharati
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Extreme Temperature ◽  
Climate Extremes ◽  
Climate Indices ◽  
Climate Projections ◽  
Temperature And Precipitation ◽  
Extreme Precipitation Events ◽  
The Impact ◽  
Precipitation Events

Abstract Existing climate projections and impact assessments in Nepal only consider a limited number of generic climate indices such as means. Few studies have explored climate extremes and their sectoral implications. This study evaluates future scenarios of extreme climate indices from the list of Expert Team on Sector-specific Climate Indices (ET-SCI) and their sectoral implications in the Karnali Basin in western Nepal. First, future projections of 26 climate indices relevant to six climate-sensitive sectors in Karnali were made for the near (2021–2045), mid (2046–2070), and far (2071–2095) future for low- and high-emission scenarios (RCP4.5 and RCP8.5, respectively) using bias-corrected ensembles of 19 regional climate models from the COordinated Regional Downscaling EXperiment for South Asia (CORDEX-SA). Second, a qualitative analysis based on expert interviews and a literature review on the impact of the projected climate extremes on the climate-sensitive sectors was undertaken. Both the temperature and precipitation patterns are projected to deviate significantly from the historical reference already from the near future with increased occurrences of extreme events. Winter in the highlands is expected to become warmer and dryer. The hot and wet tropical summer in the lowlands will become hotter with longer warm spells and fewer cold days. Low-intensity precipitation events will decline, but the magnitude and frequency of extreme precipitation events will increase. The compounding effects of the increase in extreme temperature and precipitation events will have largely negative implications for the six climate-sensitive sectors considered here.

scholarly journals Vegetation Change and Its Response to Climate Extremes in the Arid Region of Northwest China

2021 ◽  
Vol 13 (7) ◽  
pp. 1230
Author(s):  
Simeng Wang ◽  
Qihang Liu ◽  
Chang Huang
Keyword(s):  
Arid Region ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Pearson Correlation ◽  
Time Lag ◽  
Climate Extremes ◽  
Northwest China ◽  
Precipitation Extremes ◽  
Temperature Extremes ◽  
Increasing Trend

Changes in climate extremes have a profound impact on vegetation growth. In this study, we employed the Moderate Resolution Imaging Spectroradiometer (MODIS) and a recently published climate extremes dataset (HadEX3) to study the temporal and spatial evolution of vegetation cover, and its responses to climate extremes in the arid region of northwest China (ARNC). Mann-Kendall test, Anomaly analysis, Pearson correlation analysis, Time lag cross-correlation method, and Least absolute shrinkage and selection operator logistic regression (Lasso) were conducted to quantitatively analyze the response characteristics between Normalized Difference Vegetation Index (NDVI) and climate extremes from 2000 to 2018. The results showed that: (1) The vegetation in the ARNC had a fluctuating upward trend, with vegetation significantly increasing in Xinjiang Tianshan, Altai Mountain, and Tarim Basin, and decreasing in the central inland desert. (2) Temperature extremes showed an increasing trend, with extremely high-temperature events increasing and extremely low-temperature events decreasing. Precipitation extremes events also exhibited a slightly increasing trend. (3) NDVI was overall positively correlated with the climate extremes indices (CEIs), although both positive and negative correlations spatially coexisted. (4) The responses of NDVI and climate extremes showed time lag effects and spatial differences in the growing period. (5) Precipitation extremes were closely related to NDVI than temperature extremes according to Lasso modeling results. This study provides a reference for understanding vegetation variations and their response to climate extremes in arid regions.

Evaluation of multiple regional climate models for summer climate extremes over East Asia

2015 ◽  
Vol 46 (7-8) ◽  
pp. 2469-2486 ◽  
Author(s):  
Changyong Park ◽  
Seung-Ki Min ◽  
Donghyun Lee ◽  
Dong-Hyun Cha ◽  
Myoung-Seok Suh ◽  
...  
Keyword(s):  
East Asia ◽  
Climate Models ◽  
Regional Climate ◽  
Climate Extremes ◽  
Regional Climate Models ◽  
Summer Climate

Climatology and Trends of Climate Extremes of Temperature and Precipitation in Belo Monte Hydropower Plant – Eastern Amazon, Brazil

2021 ◽  
Author(s):  
Wanderson Luiz-Silva ◽  
Pedro Regoto ◽  
Camila Ferreira de Vasconcellos ◽  
Felipe Bevilaqua Foldes Guimarães ◽  
Katia Cristina Garcia
Keyword(s):  
Climate Change ◽  
Climate Extremes ◽  
Annual Rainfall ◽  
The South ◽  
North Central ◽  
Adaptation Capacity ◽  
The North ◽  
South Central ◽  
Daily Data ◽  
Belo Monte

<p>This research aims to support studies related to the adaptation capacity of the Amazon region to climate change. The Belo Monte Hydroelectric Power Plant (HPP) is in the Xingu River basin, in eastern Amazonia. Deforestation coupled with changes in water bodies that occurred in the drainage area of Belo Monte HPP over the past few decades can significantly influence the hydroclimatic features and, consequently, ecosystems and energy generation in the region. In this context, we analyze the climatology and trends of climate extremes in this area. The climate information comes from daily data in grid points of 0.25° x 0.25° for the period 1980-2013, available in http://careyking.com/data-downloads/. A set of 17 climate extremes indices based on daily data of maximum temperature (TX), minimum temperature (TN), and precipitation (PRCP) was calculated through the RClimDex software, recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The Mann-Kendall and the Sen’s Curvature tests are used to assess the statistical significance and the magnitude of the trends, respectively. The drainage area of the Belo Monte HPP is dominated by two climatic types: an equatorial climate in the north-central portion of the basin, with high temperatures and little variation throughout the year (22°C to 32°C), in addition to more frequent precipitation; and a tropical climate in the south-central sector, which experiences slightly more pronounced temperature variations throughout the year (20°C to 33°C) and presents a more defined wet and dry periods. The south-central portion of the basin exhibits the highest temperature extremes, with the highest TX and the lowest TN of the year occurring in this area, both due to the predominant days of clear skies in the austral winter, as to the advance of intense masses of polar air at this period. The diurnal temperature range is lower in the north-central sector when compared to that in the south-central region since the first has greater cloud cover and a higher frequency of precipitation. The largest annual rainfall volumes are concentrated at the north and west sides (more than 1,800 mm) and the precipitation extremes are heterogeneous across the basin. The maximum number of consecutive dry days increases from the north (10 to 20 days) to the south (90 to 100 days). The annual frequency of warm days and nights is increasing significantly in a large part of the basin with a magnitude ranging predominantly from +7 to +19 days/decade. The annual rainfall shows a predominant elevation sign of up to +200 mm/decade only in the northern part of the basin, while the remainder shows a reduction of up to -100 mm/decade. The duration of drought periods increases in the south-central sector of the basin, reaching up to +13 days/decade in some areas. The results of this study will be used in the future as an important input, together with exposure, sensibility, and local adaptation capacity, to design adaptation strategies that are more consistent with local reality and to the needs of local communities.</p>

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