The Pakistan Flood of August 2022: Causes and Implications

Earth s Future, Journal Year: 2023, Volume and Issue: 11(3)

Published: March 1, 2023

Abstract The risk of floods has increased in South Asia due to high vulnerability and exposure. August 2022 Pakistan flood shows a glimpse the enormity devastation that can further rise under warming climate. deluge caused by 2022, which badly hit country’s southern provinces, is incomparable any recent events terms vast spatial temporal scale. event ranked second human mortality, while this was top displaced about 33 million people Pakistan. Using observations climate projections, we examine causes implications Multiday (∼15 days) extreme precipitation on wet antecedent soil moisture conditions primary driver 2022. two atmospheric rivers passed over Streamflow simulations from multiple hydrological models show multiday floods. Several flood‐affected stations experienced anomalously higher flow than upstream stations. highlights adaptation challenges facing along with substantial need for mitigation reduce such events.

Language: Английский

---

Changes in Antecedent Soil Moisture Modulate Flood Seasonality in a Changing Climate

Water Resources Research, Journal Year: 2020, Volume and Issue: 56(3)

Published: Feb. 19, 2020

Due to difficulties in identifying a climate change signal flood magnitude, it has been suggested that shifts timing, is, the day of annual streamflow maxima, may be detectable. Here, we use high-quality streamflow, largely free snowmelt, from 221 catchments across Australia investigate influence soil moisture and rainfall timing on maxima timing. In tropical areas find is strongly linked both maxima. However, southern more correlated with than The link between flood, moisture, confounded by event severity: For less extreme events likely correspond whereas becomes increasingly important as severity increases. Using circular regression nonstationarity, shifting earlier year tropics later southwest continent, consistent changes mean due expansion. southeast Australia, there evidence mechanisms controlling seasonality are changing reversal trends post Millennium Drought. Overall, compared found have greater

Language: Английский

---

An extremeness threshold determines the regional response of floods to changes in rainfall extremes

Communications Earth & Environment, Journal Year: 2021, Volume and Issue: 2(1)

Published: Aug. 26, 2021

Precipitation extremes will increase in a warming climate, but the response of flood magnitudes to heavier precipitation events is less clear. Historically, there little evidence for systematic increases magnitude despite observed extremes. Here we investigate how change warming, using large initial-condition ensemble simulations with single climate model, coupled hydrological model. The model chain was applied historical (1961–2000) and warmer future (2060–2099) conditions 78 watersheds Bavaria, region comprising headwater catchments Inn, Danube Main River, thus representing an area expressed heterogeneity. For majority catchments, identify ‘return interval threshold’ relationship between increases: at return intervals above this threshold, further extreme frequency clearly yield increased magnitudes; below modulated by land surface processes. We suggest that threshold behaviour can reconcile climatological perspectives on changing risk climate. Germany rainfall processes not above,

Language: Английский

---

How Do Climate and Catchment Attributes Influence Flood Generating Processes? A Large‐Sample Study for 671 Catchments Across the Contiguous USA

Water Resources Research, Journal Year: 2021, Volume and Issue: 57(4)

Published: Feb. 10, 2021

Abstract Hydrometeorological flood generating processes (excess rain, short long snowmelt, and rain‐on‐snow) underpin our understanding of behavior. Knowledge about improves hydrological models, frequency analysis, estimation climate change impact on floods, etc. Yet, not much is known how catchment attributes influence the spatial distribution processes. This study aims to offer a comprehensive structured approach close this knowledge gap. We employ large sample (671 catchments across contiguous United States) evaluate use two complementary approaches: A statistics‐based which compares attribute distributions different processes; random forest model in combination with an interpretable machine learning (accumulated local effects [ALE]). The ALE method has been used often hydrology, it overcomes significant obstacle many statistical methods, confounding effect correlated attributes. As expected, we find (fraction snow, aridity, precipitation seasonality, mean precipitation) be most influential process distribution. However, varies both type. also can predicted for ungauged relatively high accuracy ( R 2 between 0.45 0.9). implication these findings should considered future studies, as changes characteristics

Language: Английский

---

Global Changes in 20‐Year, 50‐Year, and 100‐Year River Floods

Geophysical Research Letters, Journal Year: 2021, Volume and Issue: 48(6)

Published: March 9, 2021

Abstract Concepts like the 100‐year flood event can be misleading if they are not updated to reflect significant changes over time. Here, we model observed annual maximum daily streamflow using a nonstationary approach provide first global picture of in: (a) magnitudes 20‐, 50‐, and floods (i.e., flows given exceedance probability in each year ); (b) return periods floods, as assessed 1970 fixed magnitude (c) corresponding probabilities. Empirically, find 20‐/50‐year have mostly increased temperate climate zones, but decreased arid, tropical, polar, cold zones. In contrast, arid/temperate zones exhibit mixed trends results influenced by small number stations with long records, highlight need for continued updating hazard assessments.

Language: Английский

---