Quantifying the impact of climate change on drought regimes using the Standardised Precipitation Index

The main objective of this study was to project changes in the evolution of drought characteristics (frequency, duration and magnitude) during the 21st century in lowlands, highlands and mountainous regions in the Czech Republic (CR). We focused on the multi‐scalar nature of droughts as a function of the variables that govern the balance of moisture during climate change, such as precipitation, which supplies moisture, and temperature, which modulates evapotranspiration. Thereby, this issue is addressed with two drought indices, i.e. the standardized precipitation evapotranspiration index (SPEI) and the standardized precipitation index (SPI), for various lags (1, 3, 6, 12 and 24 months). To assess the impact of climate change on drought characteristics, a set of eight regional climate models (RCMs) simulations were selected for further analysis driven by five different global circulation models (GCMs) carried out in the frame of Euro‐CORDEX. Future drought changes were developed for the two representative concentration scenarios (RCP4.5 and RCP8.5). For the temporal evolution of the droughts, the monthly drought indices were calculated over the entire study period from 1961 to 2100. The SPEI showed a higher frequency in the categories of severe droughts and extreme droughts than the SPI, while the SPEI yielded fewer events in the extreme wet categories. The probability distribution of the SPEI‐6 under the RCP8.5 scenario shifted more than one and a half standard deviations in lowlands at the end of the century, peaking at −1.65 (with a probability of 10.5%). This meant that severe droughts, according to the current climate criteria, will become the new norm in the period 2071–2100.

Section: Discussionmentioning

confidence: 99%

Projected changes in the evolution of drought on various timescales over the Czech Republic according to Euro‐CORDEX models

Potopová

Štěpánek

Zahradníček

et al. 2018

“…Droughts were analysed using one of the most common global indexes from the last two decades, the Standardized Precipitation Index (SPI) (e.g. Hayes et al ., ; Cancelliere et al ., ; Livada and Assimakopoulos, ; Unal et al ., ; Vicente‐Serrano et al ., ; Jenkins and Warren, ; Xu et al ., ). The SPI was proposed by McKee et al () and uses precipitation data to quantify conditions of deficit or excess precipitation at different time scales or regions with different climatic conditions.…”

Section: Methodsmentioning

confidence: 99%

Climate change scenarios for Angola: an analysis of precipitation and temperature projections using four RCMs

Carvalho

Santos

Pulquério

2016

Climate change is expected to have a major impact on the world's environment, economy and society, especially in African countries such as Angola due to the dependence of many vital sectors on climate variability (e.g. agriculture) and their low adaptive capacity. With the advances in the availability of climate model data sets provided by programs such as the CORDEX, Angola can benefit from studies on future climate change using high‐spatial‐resolution data, which have previously been absent for this region. The purpose of this study is to analyse the projected changes in temperature and precipitation over Angola during the 21st century based on four regional climate models (RCMs). The spatial and temporal changes were analysed using a high‐ and medium‐low radiative forcing scenario to consider the uncertainty in greenhouse gas emissions. Changes in the average annual precipitation, average annual temperature and a drought index are studied for short‐, mid‐ and long‐term projections. Compared to the reference period, relevant changes are projected in temperature and precipitation indices for the different models under both emission scenarios. These changes include an increase in both the maximum and minimum temperature of up to 4.9 °C by the end of the century and an intensification of droughts. The precipitation projections are highly variable – increasing and decreasing – across the region and dependent on the RCMs. Despite these differences, the precipitation generally decreases over time (approximately −2% by 2100), with the southern region experiencing a stronger decrease in precipitation. Further investigation is needed to minimize projections uncertain, as the annual mean precipitation was overestimated by three of the RCMs (especially in the northern coastal units). Overall, these projected changes in climate can have important implications for the future of Angola, because they are expected to magnify existing problems, thus creating new risks for human and natural systems.

“…land-atmosphere interactions and surface processes. These studies contributed to drought understanding and prevention (Mishra and Singh, 2010;Dai, 2011;Zargar et al, 2011;Spinoni et al, 2014;Jenkins and Warren, 2015). Both spatial and temporal characteristics of droughts are a critical element for investigating drought development, propagation, and its driving forces.…”

Section: Introductionmentioning

confidence: 99%

Spatio‐temporal pattern of meteorological droughts and its possible linkage with climate variability

Zhou

Liu

2017

Spatial pattern of meteorological droughts is a critical element for investigating drought condition. Empirical orthogonal function (EOF) and rotated EOF (REOF) methods are widely used to discriminate dominant patterns. Previous works focused on case applications but left the associated physical meanings unexplored. This study employs the EOF, wavelet analysis, and stepwise regression methods to distinguish spatio‐temporal patterns of meteorological droughts with pattern interpretation. For this purpose, monthly precipitation data were used from 73 meteorological stations in the Poyang Lake basin of China for the period of 1960–2007. Standardized Precipitation Index (SPI) was applied to quantify meteorological droughts. Our results identified four leading EOF/REOF patterns at the basin scale. Seasonal SPI series showed more dominant periods than monthly SPI series, indicating periodic complexity of regional droughts. The dominant periods coincided with those of the EOF/REOF time coefficients. The four leading EOF/REOFs were significantly related to the dominant time scales of 2, 3, 6, 11, 16, and 17 years, except for the fifth EOF/REOF. Stepwise regression analysis further indicated that the four leading EOF/REOFs be likely the superposition of SPI variation from inter‐annual and inter‐decadal scales. The SPI series at different time scales (1–36 months) showed significant correlations with climate teleconnection modes, confirming the existence of identified spatio‐temporal pattern. The Niño3.4 and Southern Oscillation were the primary teleconnection modes that influenced the variability of meteorological droughts over the basin. The Pacific Decadal Oscillation and the North Atlantic Oscillation also contributed to the regional dry/wet alternation. The findings provide important implications for understanding spatial and temporal variation of regional droughts.