Climate Change Extreme Events Research Articles

Observationally constrained projection of the reduced intensification of extreme climate events in Central Asia from 0.5\xa0\xb0C less global warming

Arid Central Asia is highly vulnerable to extreme climate events. Information on potential future changes in extreme climate events in Central Asia is limited. In this study, the performances of models from the Coupled Model Intercomparison Project phase 5 (CMIP5) in simulating climatological extremes in Central Asia are first evaluated, and a bias correction method is employed to constrain future projections. The responses of extreme climate events over Central Asia to future warming and, in particular, the impact of 1.5 and 2 °C global warming scenarios are then assessed based on the observationally constrained projections. During the twenty-first century, coldest night (TNn), coldest day (TXn), warmest night (TNx), warmest day (TXx), 1-day maximum precipitation (RX1 day), 5-day maximum precipitation (RX5 day), and precipitation intensity (SDII) in Central Asia would robustly increase at best estimated rates of 1.93 °C, 1.71 °C, 1.18 °C, 1.25 °C, 6.30%, 5.71%, and 4.99% per degree of global warming, respectively, under Representative Concentration Pathway (RCP) 8.5. Compared with the 2 °C warming scenario, limiting global warming to 1.5 °C could reduce the intensification (relative to 1986–2005) of TNn, TNx, TXn, TXx, RX1 day, RX5 day, and SDII by 33%, 24%, 32%, 29%, 39%, 42%, and 53% from the best estimates under RCP8.5, respectively. The avoided intensification of TNn, TNx, TXn and TXx (RX1 day and SDII) would be larger (smaller) under RCP4.5. This suggests that a low warming target is necessary for avoiding the dangerous risk of extremes in this arid region.

Projection in Extreme Climate Events and uncertainty analysis in the Source Area of the Yellow River for the Next Three Decades

The spatial and temporal characteristics of extreme temperature and precipitation events were studied by using extreme climate indices based on the daily outputs of five general climate models (GCMs), including maximum temperature, minimum temperature and precipitation, in the period of 2021-2050 under the representative concentration pathway 4.5 (RCP4.5) scenario. The results show that compared with the period of 1971-2000, Warmest day and Warm days (the warm event) could increase by 1.4°C and 12.5d, respectively, and Frost days and Cool nights (the cold event) could decrease by 24.5d and 6.8d, respectively. The coldest night could increase by 2.1°C, the diurnal temperature range could decrease by 0.1°C. The precipitation frequency and intensity indices (Number of heavy precipitation days, Simple daily intensity indices, Max 1-day precipitation amount and Max 5-day precipitation amount) could increase by 1.1d, 3.1%, 8.4% and 6.3%, respectively. The very wet days could increase by 24.6% and the consecutive dry days could decrease by 12.3d. But, the spatial distributions of changes in extreme climate events are uneven. Although projected changes are still uncertain to some extent, the trends among different GCMs show a good consistency.

Trends in extreme climatic indices across the temperate steppes of China from 1961 to 2013

Extreme climate events have become more severe and frequent with global change in recent years. The Chinese temperate steppes are an important component of the Eurasian steppes and highly sensitive and vulnerable to climatic change. As a result, the occurrence of extreme climate events must have strong impacts on the temperate steppes. Therefore, understanding the spatio-temporal trends in extreme climate is important for us to assess the sensitivity and vulnerability of Chinese temperate steppes to climatic changes. This research had two specific objects to (i) specify the temporal changes in extreme climate events across the whole steppe and (ii) compare the trend differences for extreme climate events in different types of steppes—meadow steppe, typical steppe and desert steppe. To investigate extreme climate trends in the temperate steppes of China, 82 meteorological stations with daily temperature and precipitation data (1961–2013) were used. Meanwhile, eight core extreme climate indices (extreme high-temperature threshold, extreme low-temperature threshold, frost days, heatwave duration, heavy rainfall threshold, percentage of heavy rainfall, heavy rainfall days and consecutive dry days) from the Statistical and Regional Dynamical Downscaling of Extremes for European Regions (STARDEX) project were selected to analyse the trends in extreme climate across the whole temperate steppe and the three main types (meadow steppe, typical steppe and desert steppe) through time and space. The results showed that (i) the changes in extreme climatic temperature events across the whole temperate steppe were obvious during 1961–2013. The frost days (−3.40 days/10 year [yr]) decreased significantly, while the extreme high-temperature threshold (0.24°C/10 yr), extreme low-temperature threshold (0.52°C/10 yr), and heatwave duration (0.58 days/10 yr) increased notably. The annual changes in extreme precipitation were small and not significant. (ii) Differences appeared in the extreme climatic trends in different types of steppes. The desert steppe showed strong climate extremes and underwent the most significant asymmetric warming compared with the meadow steppe and typical steppe. At the same time, the heatwave duration (0.62 days/10 yr) increased. In terms of the extreme precipitation, there was no significant trend among the three types of steppes. However, the fluctuations in extreme precipitation were the largest in the desert steppe compared to those in the typical steppe and meadow steppe.

Analysis of changes in daily temperature and precipitation extreme in Jakarta on period of 1986-2014

Climate change due to an increase in greenhouse gas concentrations has led to changes in extreme climate events. IPCC 2007 already predicted that average global temperatures would reach 0.74⁰ C in the last 100 years (1906-2005). A study on the temperature index trends and extreme precipitation in the period of 1986-2014 in Jakarta are represented by 5 weather stations. Daily of maximum temperature, minimum temperature, and precipitation data are calculated using RClimDex Software so that temperature and rainfall index data are obtained. The indexes are extreme climate indexes defined by ETCCDMI (Expert Team for Climate Change Detection Monitoring and Indices). The indexes consist of TN10p, TN90p, TX10p, TX90p, TNn, TNx, TXn, TXx, DTR, RX1day, RX5day, RCPTOT, CDD, CWD, and R95p. The purpose of this research is to know the change of temperature and precipitation characteristics from observation result in Jakarta by using index calculation. The results show that Jakarta has number of hot days according to the trends which are generally increasing. It can cause the temperature in Jakarta to get hotter. However, for the rainfall, the upward or downward trend is not significant, so it can be said there is no change in precipitation in Jakarta during 1986-2014.

Changes in “hotter and wetter” events across China

As global warming intensifies, efforts to understand the changes in extreme climate events have increased in recent years. A combined analysis of the changes in extreme temperature and precipitation events is presented in this paper. Using observational data from 1961 to 2015, a set of hotter and wetter (HW) events is defined, and we examine the changes in these events across China. The results show that more HW events occur in Central and Eastern China than in other subregions, especially in South China (SC). The rate of increase in HW events is 2.7 and 1.9 per decade in SC and East China (EC), respectively. In China, most HW events occurred in the last 20 years of the study period, indicating that China entered a period of high-frequency HW events. Indeed, the range in anomalies in the torrential rain days is greater than that of the high-temperature days in Northwest China (NWC), Central China (CC), and EC after the mid- to late 1990s. The opposite pattern is found in Northeast China (NEC), Southwest China-region 1 (SWC1), Southwest China-region 2 (SWC2), and SC. Finally, the increase in HW events in most regions of China is closely associated with warming.

TREND ANALYSIS OF EXTREAM RAINFALL FROM 1982 - 2013 AND PROJECTION FROM 2014 - 2050 IN BANDA ACEH AND MEULABOH

Abstract. Climate change is a global phenomenon that currently and seriously impacts the environment. Increasing concentrations of greenhouse gases have caused changes in extreme climate events. We have studied index rainfall extream trend at two meteorological stations of Sultan Iskandar Muda in Banda Aceh and Cut Nyak Dien in Meulaboh from 1982-2013. Daily rainfall data were processed using software of RClimDex to obtain the extreme rainfall index. Such indexes are extreme climate index set by the expert team for Climate Change Detection Monitoring and Indices (ETCCDMI) including of maximum 1-day and 5-days precipitation amount (RX1day and RX5day), total annual precipitation (PRCPTOT), consecutive dry days (CDD), consecutive wet days (CWD), very wet days (R95p), extremely wet days (R99p) and heavy precipitation days (R20mm). Based on our study, we found that the PRCPTOT tend to decrease, whereas occurances of RX1day and RX5day increase. The Banda Aceh station which has a monsoonal pattern is charaterized by increasing in R95p and R99p as well as but decreasing in R20mm. The CWD and CDD tend to accumulate at once. The Meulaboh station that has the type of equatorial rain show decreasing trend in R95p and R99p, but increasing trend in R20mm. The CWD and CDD occur within some days. The projection Representative Concentration Pathways (RCP) 4.5 and 8.5 from 2014-2050 showed an increasing pattern frequency of rain in Banda Aceh and a decreasing pattern in Meulaboh. Keywords: Trend, Extream Climate Index, ProjectionREFERENCE Lutgens. F.K. and Tarbuck. E.J. 2004. The Atmosphere: An Introduction to Meteorology. Pearson Prentice Hall. New Jersey.Ratag, M.A., Halimurrahman, Juaeni, I., Siswanto, B., dan N., Adikusumah. 2002. Perubahan Iklim : Basis Alamiah dan Dampaknya. Bandung, Lembaga Penerbangan dan Antariksa Nasional.IPCC, 2013. Climate Change. World Meteororogical Organization. Switzerland.Nuraini, Ida Sartika. 2014. Analisis dan Proyeksi Trend Temperatur dan Curah Hujan untuk Mendeteksi Perubahan Iklim (Studi Kasus Provinsi Kalimantan Barat). STMKG, Tangerang Selatan.Sulistya, W., Swarinoto, T.S., Zakir, A.,Riyanto, H., dan B., Ridwan.1998. The Impact of El Nino 1997/98 over Indonesia Region. Jakarta: Jurnal Meteorologi dan Geofisika, No 4, Desember.Zhang, X., and Feng Yang, 2004. RClimDex User Manual. Climate Research Branch, Environment Canada, Downsview, Ontario, Canada.Aldrian, E., 2007 Perubahan iklim global dan dampak terhadap iklim benua mantim di laut dan di daratan Prosiding Jumal Club Tahun 2007.Badan Meteorologi dan Geofisika. ISBN:978-979-1241-11-3

Analyses of Observed and Anticipated Changes in Extreme Climate Events in the Northwest Himalaya

In this study, past (1970-2005) as well as future long term (2011-2099) trends in various extreme events of temperature and precipitation have been investigated over selected hydro-meteorological stations in the Sutlej river basin. The ensembles of two Coupled Model Intercomparison Project (CMIP3) models: third generation Canadian Coupled Global Climate Model and Hadley Centre Coupled Model have been used for simulation of future daily time series of temperature (maximum and minimum) and precipitation under A2 emission scenario. Large scale atmospheric variables of both models and National Centre for Environmental Prediction/National Centre for Atmospheric Research reanalysis data sets have been downscaled using statistical downscaling technique at individual stations. A total number of 25 extreme indices of temperature (14) and precipitation (11) as specified by the Expert Team of the World Meteorological Organization and Climate Variability and Predictability are derived for the past and future periods. Trends in extreme indices are detected over time using the modified Mann-Kendall test method. The stations which have shown either decrease or no change in hot extreme events (i.e., maximum TMax, warm days, warm nights, maximum TMin, tropical nights, summer days and warm spell duration indicators) for 1970–2005 and increase in cold extreme events (cool days, cool nights, frost days and cold spell duration indicators) are predicted to increase and decrease respectively in the future. In addition, an increase in frequency and intensity of extreme precipitation events is also predicted.

Extreme climate events and agricultural climate indices in China: CMIP5 model evaluation and projections

This study evaluates the 14 global climate models in the Coupled Model Intercomparison Project Phase 5 in capturing the extreme climate events and the agricultural climate indices over China. Future climate event changes in different Representative Concentration Pathway scenarios in China are projected using the Reliability Ensemble Average method. The models can simulate the basic spatial distribution characteristics of indices and simulate temperature indices better than precipitation indices. The models overestimate the number of wet days over China, which is related to the tendency that rainfall is simulated too often and too lightly in models. The underestimation of the number of very heavy precipitation events is detected in most models, while overestimation occurred in northern China and the Qinghai-Tibet Plateau region. Some factors, such as the complex topography, the moist convection schemes in models, and the ability to simulate large-scale circulation, may result in the performances for precipitation. Higher active accumulated temperature and more summer days are projected, while the accumulated negative temperature and frost days are projected to decrease with the warming climate. Northern China would become wetter when the number of wet days (R1mm) increases. Extreme wet events are projected to be more probable in South and Central China and the Southwest Region, with increases in very heavy precipitation days (R20mm) in all scenarios. These changes in extreme climate events and agricultural climate indices would inevitably affect agriculture in China.

Changes in extreme climate events in eastern China during 1960–2013: A case study of the Huaihe River Basin

Within the context of global warming, climate extremes, including extreme wet event and drought events, have become one of the most significant and attractive themes around the world. The target region of this study is confined to eastern China, with most of the country's population concentrated, where both the wet and drought climate extremes can cause considerable damages to the economy, particularly to agriculture. From the inter-annual and intraseasonal scale, temporal and spatial distributions of climate extremes for 27 stations in the Huaihe River Basin over the period 1960–2013, are examined rigorously by means of a modified FAO Penman-Monteith method and the standardized variables of the monthly Surface Humid Index. Morlet wavelet analysis is utilized to thoroughly investigate the oscillation and periodicity of extreme wet/drought events during four seasons, as well as the whole year. The results suggest that the frequency of extreme wet events has significantly increased by 0.0118 times/year, whereas the trend for extreme drought events has gradually decreased, at the rate of 0.0127 times/year, both of which are in accordance with inter-decadal variations of climate extremes. Comparative study reveals climate extremes in autumn shows great differences, in sharp contrast to other seasons and the general inter-annual tendency. Spatial distributions of inter-annual extreme climate events exhibit certain symmetry characteristics, from west to east, indicating the combined influences of topography and monsoon circulation. The major cycles of extreme wet and drought events are 14 years and 24 years, respectively. Finally, possible causes of the temporal and spatial distributions of climate extremes are tentatively analyzed, by correlation analysis of six indexes, namely, AOI, AAOI, EASMI, WNPMI, SASMI, and NAOI, with AOI and NAOI being the dominant indexes under the background of large-scale atmospheric circulation. Additionally, other factors such as total annual precipitation, northward movement and enhancement of the subtropical anticyclone, and anthropogenically induced greenhouse forcing can also contribute to the changes in extreme climate events.

Performance evaluation of high-resolution regional climate simulations in the Alpine space and analysis of extreme events

This study aimed to assess the capabilities of high-resolution simulations in reproducing the main features of the climate in the complex topography region of the Alps for the period 1971–2000. This is to provide a reliable tool for impact studies on local scale. Two simulations, driven by ERA-40 Reanalysis, have been carried out, respectively, at spatial resolutions of 0.125° and 0.0715° with the regional climate model COSMO-CLM. The model response has been analyzed in terms of 2 m temperature and precipitation, and comparisons with available observations have been carried out. A number of climate indices have also been analyzed, widely adopted to monitor changes in extreme climate events. Finally, the effects of increasing spatial resolution have also been investigated. The model at high spatial resolution (0.0715°) provides a satisfactory representation of temperature. The simulated precipitation patterns are also improved due to the high model resolution that allows reproducing localized precipitation phenomena with a medium-high error, especially where summer thunderstorms over the complex topography of the Alpine region occurs.

Spatial and temporal distributions of trends in climate extremes of the Feilaixia catchment in the upstream area of the Beijiang River Basin, South China

ABSTRACTTo evaluate the changes in extreme climatic events in the Feilaixia catchment in South China, the spatial and temporal distributions of extreme climate indices trends during 1969–2011 were investigated. With quality control and homogeneity assessment, daily maximum and minimum surface air temperature from 11 meteorological stations and daily precipitation from 24 rainfall stations were used. Eight indices of extreme temperature and six indices of extreme precipitation were chosen. Trends were calculated using Sen's slope estimator. Statistical significance of trends was checked with the Mann–Kendall method. High correlations were found between the mean annual temperature and temperature extremes, as well as between the annual total precipitation and precipitation extremes in most cases. The analyses of extreme temperature indices detected significant and stable trends in the majority of the stations. The strongly stable downward trends in cold extremes and the strongly stable upward trends in hot extremes were recorded in the whole region, except for in some small areas primarily located in the central part of the region. In contrast, significant and stable positive trends were sporadically recorded for precipitation extremes in the study area during 1969–2011, which predominantly occurred in the northern part of the region. Furthermore, the positive trends were much more frequent than the negative trends in most extreme precipitation indices. There were significant and stable trends recorded in most of the average temperature extremes, whereas insignificant and unstable trends were found for most of the average precipitation extremes.

Changes in climate classification and extreme climate indices from a high-resolution future projection in Korea

We investigate the future changes in the climate zone and six extreme temperature indices in Korea, using the 20-km high-resolution atmospheric general circulation model (MRI-AGCM3.1S). The Trewartha and Koppen climate classification schemes are applied, and four summer-based extreme temperature indices (i.e., summer days, tropical nights, growing degree days, and cooling degree days (CDD) and two winter-based indices (frost days and heating degree days (HDD) are analyzed. To represent significantly the change in threshold indices, the monthly mean bias is corrected in model. The model result reasonably captures the temporal and spatial distribution of the present-day extreme temperatures associated with topography. It was found that in the future climate, the area of the subtropical climate zone in Korea expands northward and increases by 21% under the Trewartha classification scheme and by 35% under the Koppen classification scheme. The spatial change in extreme climate indices is significantly modulated by geographical characteristics in relation to land-ocean thermal inertia and topographical effects. The change is manifested more in coastal regions than in inland regions, except for that in summer days and HDD. Regions with higher indices in the present climate tend to reveal a larger increase in the future climate. The summer-based indices display an increasing trend, while the winter-based indices show a decreasing trend. The most significant increase is in tropical nights (+452%), whereas the most significant decrease is in HDD (−25%). As an important indicator of energy-saving applications, the changes in HDD and CDD are compared in terms of the frequency and intensity. The future changes in CDD reveal a higher frequency but a lower temperature than those in HDD. The more frequent changes in CDD may be due to a higher and less dispersed occurrence probability of extreme temperatures during the warm season. The greater increase in extreme temperature events during the summer season remains an important implication of projecting future changes in extreme climate events.

Characteristic Features of Precipitation Extremes over India in the Warming Scenarios

The detection of possible changes in extreme climate events, in terms of the frequency, intensity as well as duration assumes profound importance on the local, regional, and national scales, due to the associated critical socioeconomic consequences. Therefore, an attempt is made in this paper to evaluate various aspects of future projections of precipitation extremes over India, as projected by a state-of-art regional climate modeling system, known as PRECIS (Providing REgional Climates for Impacts Studies) towards the end of the 21st century (that is, 2071–2100) using standardized indices. Study reveals that PRECIS simulations under scenarios of increasing greenhouse gas concentration and sulphate aerosols indicate marked increase in precipitation towards the end of the 21st century and is expected to increase throughout the year. However the changes in daily precipitation and the precipitation extremes during summer monsoon (June through September) season are prominent than during the rest of year. PRECIS simulations under both A2 and B2 scenarios indicate increase in frequency of heavy precipitation events and also enhancement in their intensity towards the end of the 21st century. Both A2 and B2 scenarios show similar patterns of projected changes in the precipitation extremes towards the end of the 21st century. However, the magnitudes of changes in B2 scenario are on the lower side.

A future climate scenario of regional changes in extreme climate events over China using the PRECIS climate model

Based on the PRECIS climate model system, we simulate the distribution of the present (1961∼1990) and future (2071∼2100) extreme climate events in China under the IPCC SRES B2 scenario. The results show that for the present case PRECIS simulates well the spatial distribution of extreme climate events when compared with observations. In the future the occurrence of hot events is projected to be more frequent and the growing season will lengthen, while the occurrence of cold events is likely to be much rarer. A warming environment will also give rise to changes in extreme precipitation events. There would be an overall increasing trend in extreme precipitation events over most of China. The southeast coastal zone, the middle and lower reaches of the Yangtze River and North China are projected to experience more extreme precipitation than the present.

Climatic and oceanic associations with daily rainfall extremes over Southern Africa

AbstractChanges in climate variability and, in particular, changes in extreme climate events are likely to be of far more significance for environmentally vulnerable regions than changes in the mean state. It is generally accepted that sea‐surface temperatures (SSTs) play an important role in modulating rainfall variability. Consequently, SSTs can be prescribed in global and regional climate modelling in order to study the physical mechanisms behind rainfall and its extremes. Using a satellite‐based daily rainfall historical data set, this paper describes the main patterns of rainfall variability over southern Africa, identifies the dates when extreme rainfall occurs within these patterns, and shows the effect of resolution in trying to identify the location and intensity of SST anomalies associated with these extremes in the Atlantic and southwest Indian Ocean. Derived from a Principal Component Analysis (PCA), the results also suggest that, for the spatial pattern accounting for the highest amount of variability, extremes extracted at a higher spatial resolution do give a clearer indication regarding the location and intensity of anomalous SST regions. As the amount of variability explained by each spatial pattern defined by the PCA decreases, it would appear that extremes extracted at a lower resolution give a clearer indication of anomalous SST regions. Copyright © 2006 Royal Meteorological Society.

Climate Change Scenarios for the UK

The purpose of this paper is to present time-dependent scenarios of climate change for the UK, including possible changes in extreme climatic events. Initially, the methods of scenario construction are described. These involve the scaling of the regional patterns of equilibrium climate change produced by general circulation models (GCMs) by the time-dependent projection of global-mean temperature change. A 'Business-as-Usual' forcing scenario is then used to project global warming to the year 2050. This projection is used to develop scenarios of the UK temperature and precipitation change. The implications for sea level are also discussed. Finally, the climate change 'commitment' for the UK, due to past radiative forcing changes and the lags in the climate system, is considered.