An increasing trend in daily monsoon precipitation extreme indices over Pakistan and its relationship with atmospheric circulations

Abstract

This study assessed spatiotemporal trends in daily monsoon precipitation extremes at seasonal and sub-seasonal scales (June, July, August, and September) and their links with atmospheric circulations over Pakistan. The study used observed precipitation data from fifty in-situ stations and reanalysis products from the European Centre for Medium-Range Weather Forecasts (ECMWF) and National Centers for Environmental Prediction/the National Center for Atmospheric Research (NCEP/NCAR) during 1981–2018. A suite of seven extreme precipitation indices and non-parametric statistical techniques were used to infer trends in the frequency and intensity of extreme precipitation indices. An increase in frequency and intensity of overall extreme indices was evident, with a maximum tendency in the country’s northwestern (z-score=>2.5), central, and eastern (z-score > 4) monsoon-dominant parts. The northern and southwestern parts of the country exhibited a slight decrease (z-score <–2) in frequency and intensity. The Sen’s Slope estimator (SSE) shows an increase in western parts (0.20 days) indicating a shift in the maxima of the monsoon precipitation. The regional precipitation shows an increase in wet days (R1 mm) with higher values of mMK (3.71) and SSE (0.3) in region 2 Similar results of moderate regional increase are evident for extreme indices except regions 1 and 3. The extreme 1-day maximum precipitation increased in region 3 (mMK: 1.39, SSE: 2.32). The extremely wet days (R99p TOT) precipitation has a moderate increase in all regions with a decrease in region 1. The temporal mutations showed dynamic changes, clearly reflecting the country’s historical extreme events. The frequency and intensity of precipitation extremes negatively correlated with the altitude (R = −0.00039). The probability density function (PDF) showed a significant increase in the density during June and September with a probabilistic positive shift during July and August. The intensified mid-latitude westerlies and subtropical zonal easterlies teleconnections, strengthening of the monsoon trough, and land-ocean thermal contrast are the potential drivers of the increasing trend in precipitation extremes. The current study could serve as a benchmark for future researchers and policymakers to devise effective mitigation strategies for sustainable development.

Resilience-Vulnerability Balance and Obstacle Factor Analysis in Urban Flooding: A Case Study in the Qinghai–Tibetan Plateau

“…(2) A total of 33 counties (73%) have low or medium levels of resilience, and 4 (9%) and 8 (18%) counties have very high or high resilience levels, respectively, in Qinghai. (3) The spatial distribution of flood vulnerability and resilience in Qinghai is spatially unbalanced. The main factors affecting urban resilience in Qinghai include the number of hospital beds, the length of flood levees, and per capita GDP.…”

“…Globally, the frequency of natural catastrophes has increased significantly over the past three decades, with floods being the most frequent type of disaster [2]. The increased risk of climate change, coupled with ecological degradation and low coping capacities, has resulted in an increased risk of flooding globally and an increase in the number of regions affected by floods [3,4]. According to statistical information from China's flood and drought disaster bulletin, more than 100 cities in China are affected by flooding every year [5].…”

Flood vulnerability assessment in the flood prone area of Khyber Pakhtunkhwa, Pakistan

“…Between 1990 and 2020, there has been a notable rise in natural disasters, with flooding being the most frequent phenomenon (Abbas et al, 2023a;Rahman et al, 2023). The scientific community has warned that the increasing risk of climate change coupled with deforestation and low coping capacity would double the risk of global flooding Ullah et al, 2023) and increase the number of areas susceptible to flooding by 2050 (UNESCO, 2009). In the modernday context, the demand for sustainable catastrophe management has emerged, and professionals across several disciplines, including researchers, geographers, climatologists, and regional planners, are actively involved in global projects aimed at regulating and mitigating the effects of disasters (Roy et al, 2020).…”