Modelling the impacts of the Pacific Ocean sea surface temperature anomalies on a drought event in southwestern China with a piecewise‐integration method

Gan, Ruhui; Yang, Yi; Ma, Yuanyuan

doi:10.1002/joc.5843

Cited by 6 publications

(4 citation statements)

References 67 publications

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“…However, the causes of the anomalous Indian monsoon and EB is still unclear. Previous studies recognized that the tropical Pacific SSTA is an important factor in anomalous atmospheric circulation [55,56]. As the third year of a rare triple La Niña, the cold SST anomaly in the Equatorial Eastern Pacific is developed in the summer of 2022.…”

Section: Discussionmentioning

confidence: 99%

Different Characteristics and Drivers of the Extraordinary Pakistan Rainfall in July and August 2022

Chen

et al. 2023

Remote Sensing

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The unprecedented and long-lasting abnormal monsoon rainfall attacked Pakistan in the summer of 2022, causing severe flooding. This study investigated the sub-seasonal characteristics and mechanisms of this distinctively extreme precipitation event. The historical rainfall in July and August and extreme precipitation mainly occurred in northern Pakistan. Both the monthly rainfall in July and August 2022 and the extreme precipitation during the summer were far exceeding the historical record and involved unique spatial distribution. The rainfall in July 2022 is nationwide and mainly located in northern Pakistan, while the rainfall in August and extreme precipitation occurred in southern Pakistan. Different physical processes are responsible for the precipitation in July and August 2022. In July, the South Asian high (SAH) and Iranian high extended eastward. Meanwhile, the anticyclonic circulation anomalies occurred in northwestern Pakistan and the easterly winds enhanced in the south side of the Tibetan Plateau (TP), which strengthened water vapor transporting from the Bay of Bengal and cooperated with the cyclonic system over the Arabian Sea to enhance the precipitation over Pakistan. In August, the SAH further extended eastward and the Western Pacific Subtropical High extended westward to the TP. Meanwhile, the European blocking (EB) developed, and a deep trough appeared over northwestern Pakistan. This weakened the easterly flow along southern TP but enhanced the southerly flow accompanying the cyclone over the Bay of Bengal and the Arabian Sea, and thus guided the water vapor transporting to southern Pakistan and enhanced the precipitation. The extreme precipitation in July was mainly attributed to the unusually strong Indian monsoon, while the extreme precipitation in August was the result of a combination of the Indian monsoon and EB. The study provided important information about extreme precipitation in Pakistan, which will help policymakers take measures to deal with the effects of flooding.

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Section: Discussionmentioning

confidence: 99%

Different Characteristics and Drivers of the Extraordinary Pakistan Rainfall in July and August 2022

Chen

et al. 2023

Remote Sensing

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“…The PWI has been proved to be effective in reducing the simulation errors (Gan et al 2019;Shao et al 2015;Zhang et al 2008). In the following section, a complex climate model is used to test the simulations of GHGs-induced global climate change using both the CONT and the PWI.…”

Section: The Pwi Approachmentioning

confidence: 99%

A piecewise integration approach for model error-induced biases of greenhouse gas contribution to global warming

Liu

Wang

et al. 2022

Clim Dyn

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Many of the observed changes of the climate system since the 1950s are unprecedented, and there is a high level of con dence in the conclusion that greenhouse gases (GHGs) caused a substantial part of the observed global warming. We need to consider the model errors, that usually accumulate in long-term integration as a result of imperfect physical and numerical representations, to attribute climate changes using model simulations. Here, we present a new method of the piecewise integration (PWI) with simulation corrected by the observation at each step, to identify model error-induced bias of global warming in the Community Earth System Model (CESM). To con rm the hypothesis of constant modelobservation bias under different external forcing, we disturb the original CESM into a less low-cloud version and take its historical and GHGs-xed simulations as our "observations". In the PWI historical and GHGs-xed runs of original CESM from 1958 to 2005, we use the difference between "historical observation" and PWI historical run to correct both PWI runs at the end of each 1-day step. The results show that the PWI can effectively reduce model's cumulative error and presents a GHGs-induced global warming trend of 0.688℃ (48yr) -1 , which is very close to the "observational" trend of 0.683℃ (48yr) -1 , con rming the hypothesis of constant model bias under different external forcing. The continuous runs, as usually done by the Coupled Model Intercomparison Project (CMIP) models, present a much higher GHGs-induced global warming trend of 0.887℃ (48yr) -1 , which means that the model overestimates the GHGs's role in global warming trend by 32.3% compared to our "observations". Global distribution of this model bias is also discussed. The PWI method provides a new way to correct model biases in analyzing relative contribution of anthropogenic and natural forcing to global warming.

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“…Against the background of global climate change and the increasing intensity of human activities, many scholars have considered various methods to study the attribution of drought, and have achieved substantive results. Gan used the continuous integral method and piecewise integral method to attribute drought events in Southwest China from 2009 to 2010 [20]. The experiment revealed that insufficient precipitation and high temperatures are the main driving forces of the formation and maintenance of drought.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the Effects of Climate Variability, Land-Use Changes, and Human Activities on Drought Based on the SWAT–PDSI Model

Zhu

Lian

et al. 2022

Remote Sensing

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Much attention has recently been devoted to the qualitative relationship between climate factors and drought; however, the influences of climate variability, land-use/cover changes (LUCC), and other human activities on drought have rarely been quantitatively assessed. Based on the Soil and Water Assessment Tool (SWAT) model and the Palmer drought severity index (PDSI), this study presents a framework to quantify drought changes in an attribution study, and quantifies the effects of climate factors, LUCC, and other human activities on drought in a typical basin (Yihe River) in eastern China from 1980 to 2019. (1) The SWAT–PDSI results revealed a slight decreasing trend from 1980 to 2019, indicating that the degree of drought increased—especially in the middle of the basin. (2) The precipitation in the basin exhibited a downward trend (−2.7 mm/10 a), while the temperature exhibited a significant increasing trend (0.13 °C/10 a, p < 0.05). Over the past 40 years, LUCC in the Yihe River Basin was mainly characterized by a reduction in the dryland area (149 km2) and an increase in the built-up area (135 km2), which changed by −1.77% and 18.96%, respectively. (3) Climate fluctuation was the main driving factor of drought change, with a contribution rate ranging from 68 to 84%, and the contribution to drought gradually increased. Among the various factors, the contribution of temperature exceeded that of precipitation from 2010 to 2019, suggesting that temperature has become the most important climate factor affecting drought. The contribution rates of LUCC to drought changes over the periods 1990–1999, 2000–2009, and 2010–2019 were 7.8%, 18%, and 12.6%, respectively. This indicates that the relative contributions of other human activities to drought changes gradually decreased. This study refines the drought attribution framework, which could provide scientific support for the quantitative attribution of drought and the formulation of disaster prevention and reduction strategies.

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Modelling the impacts of the Pacific Ocean sea surface temperature anomalies on a drought event in southwestern China with a piecewise‐integration method

Cited by 6 publications

References 67 publications

Different Characteristics and Drivers of the Extraordinary Pakistan Rainfall in July and August 2022

Different Characteristics and Drivers of the Extraordinary Pakistan Rainfall in July and August 2022

A piecewise integration approach for model error-induced biases of greenhouse gas contribution to global warming

Quantifying the Effects of Climate Variability, Land-Use Changes, and Human Activities on Drought Based on the SWAT–PDSI Model

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