Large-scale atmospheric circulation patterns associated with extreme monsoon precipitation in Pakistan during 1981–2018

Ullah, Waheed; Wang, Guojie; Lou, Dan; Ullah, Safi; Bhatti, Asher Samuel; Ullah, Sami; Karim, Aisha; Hagan, Daniel Fiifi Tawia; Ali, Gohar

doi:10.1016/j.atmosres.2021.105489

Cited by 71 publications

(78 citation statements)

References 71 publications

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“…Precipitation (P) variability is partly impacted by the interaction with global climate forcing systems, such as the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). These teleconnections in space and time are widely reported to explain the annual and seasonal P variability in SSA [29,30].…”

Section: Study Areamentioning

confidence: 91%

“…To examine specific drought characteristics and trends in detail, three regions were selected (see Figure 1a). The boxes in Figure 1a The justification for selecting the limits of the boxes was based on their interannual P variations, the mean climate, and the associations with teleconnections [29][30][31][32]. The SSG region used in this paper includes the Sahelian belt, the Sudanian belt, and parts of the Guinean coast stretching from the Atlantic Ocean to the central region at longitudes of 20 • E. The HoA used here extends from the interior of the Ethiopian and Kenyan highlands to the coast of the Indian Ocean.…”

Section: Study Areamentioning

confidence: 99%

“…The SSG region used in this paper includes the Sahelian belt, the Sudanian belt, and parts of the Guinean coast stretching from the Atlantic Ocean to the central region at longitudes of 20 • E. The HoA used here extends from the interior of the Ethiopian and Kenyan highlands to the coast of the Indian Ocean. The SAR includes areas that lie below 15 • S. The justification for selecting the limits of the boxes was based on their interannual P variations, the mean climate, and the associations with teleconnections [29][30][31][32].…”

Section: Study Areamentioning

confidence: 99%

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Spatiotemporal Characteristics and Trend Analysis of Two Evapotranspiration-Based Drought Products and Their Mechanisms in Sub-Saharan Africa

et al. 2021

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Drought severity still remains a serious concern across Sub-Saharan Africa (SSA) due to its destructive impact on multiple sectors of society. In this study, the interannual variability and trends in the changes of the self-calibrating Palmer Drought Severity Index (scPDSI) based on the Penman–Monteith (scPDSIPM) and Thornthwaite (scPDSITH) methods for measuring potential evapotranspiration (PET), precipitation (P), normalized difference vegetation index (NDVI), and sea surface temperature (SST) anomalies were investigated through statistical analysis of modeled and remote sensing data. It was shown that scPDSIPM and scPDSITH differed in the representation of drought characteristics over SSA. The regional trend magnitudes of scPDSI in SSA were 0.69 (scPDSIPM) and 0.2 mm/decade (scPDSITH), with a difference in values attributed to the choice of PET measuring method used. The scPDSI and remotely sensed-based anomalies of P and NDVI showed wetting and drying trends over the period 1980–2012 with coefficients of trend magnitudes of 0.12 mm/decade (0.002 mm/decade). The trend analysis showed increased drought events in the semi-arid and arid regions of SSA over the same period. A correlation analysis revealed a strong relationship between the choice of PET measuring method and both P and NDVI anomalies for monsoon and pre-monsoon seasons. The correlation analysis of the choice of PET measuring method with SST anomalies indicated significant positive and negative relationships. This study has demonstrated the applicability of multiple data sources for drought assessment and provides useful information for regional drought predictability and mitigation strategies.

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Section: Study Areamentioning

confidence: 91%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

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Spatiotemporal Characteristics and Trend Analysis of Two Evapotranspiration-Based Drought Products and Their Mechanisms in Sub-Saharan Africa

et al. 2021

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“…Simultaneously, the significance of these linear trends was examined by Mann-Kendall trend analysis [65][66][67]. For the detailed computation procedure, please refer to the studies of [68][69][70].…”

Section: Statistical Analysis Of Historical and Projection Of Etmentioning

confidence: 99%

Future Changes in Simulated Evapotranspiration across Continental Africa Based on CMIP6 CNRM-CM6

Nooni

Hagan

Wang

et al. 2021

IJERPH

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The main goal of this study was to assess the interannual variations and spatial patterns of projected changes in simulated evapotranspiration (ET) in the 21st century over continental Africa based on the latest Shared Socioeconomic Pathways and the Representative Concentration Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) provided by the France Centre National de Recherches Météorologiques (CNRM-CM) model in the Sixth Phase of Coupled Model Intercomparison Project (CMIP6) framework. The projected spatial and temporal changes were computed for three time slices: 2020–2039 (near future), 2040–2069 (mid-century), and 2080–2099 (end-of-the-century), relative to the baseline period (1995–2014). The results show that the spatial pattern of the projected ET was not uniform and varied across the climate region and under the SSP-RCPs scenarios. Although the trends varied, they were statistically significant for all SSP-RCPs. The SSP5-8.5 and SSP3-7.0 projected higher ET seasonality than SSP1-2.6 and SSP2-4.5. In general, we suggest the need for modelers and forecasters to pay more attention to changes in the simulated ET and their impact on extreme events. The findings provide useful information for water resources managers to develop specific measures to mitigate extreme events in the regions most affected by possible changes in the region’s climate. However, readers are advised to treat the results with caution as they are based on a single GCM model. Further research on multi-model ensembles (as more models’ outputs become available) and possible key drivers may provide additional information on CMIP6 ET projections in the region.

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“…The monsoon onset across the region has been linked with several factors, including the sea surface temperature, westerlies progression, convection, and local continentalscale tipping elements. Less attention has been paid to the in uence of the TP soil moisture-induced thermal pro le in uence on the monsoon onset across time (Zhang et al 2002;Stolbova et al 2016;Ullah et al 2020Ullah et al , 2021. The following section shows a diagnostic relationship of the soil moisture pro le over the TP and its thermodynamics role in the SA monsoon onset.…”

Section: Precipitation Climatologymentioning

confidence: 99%

The Empirical Influences of Tibetan Plateau Soil Moisture on South Asian Monsoon Onset

Lou¹,

Wang²,

Ullah³

et al. 2021

Preprint

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The South Asian High (SAH) location and intensity are linked with the Tibetan Plateau (TP) and Yangtze River basin latent heating. The existing feedbacks of SAH variability is rarely linked with TP soil moisture regulated energy fluxes. In this study, remotely sensed soil moisture and global atmospheric reanalysis products are used to quantify the relationship between the TP spring (April, May, June) soil moisture with SAH and South Asian (SA) monsoon onset during 1988–2008. The diagnostic analysis infers that the SAH exhibits a significant correlation (R ≥ 0.90) with TP spring soil moisture and monsoon onset indices (R≥ -0.56−-0.61). During the early and late monsoon onset, a significant anomalous soil moisture regime influenced the surface energy fluxes, which affected the vertical diabatic heating profile. The diabatic heating profile affects the TP ascending motion and SAH intensity, which leads to regional monsoon circulation changes and onset. An asymmetric SAH movement in the upper troposphere appears before the early and late monsoon onset composites and drives the lower tropospheric westerlies/easterlies winds towards the continental SA. The wind shear and transition from prevailing easterlies into westerlies during the pre-onset, onset, and post-onset pentad results in strong/weak ascent in the Bay of Bengal and advances into continental regions. The onset- mechanism further suggested intensified/weaker westerlies/easterlies during early/late onset composites. The SAH intensity and movement are linked with TP soil moisture, which exhibits teleconnections with the regional circulation pattern. A detailed model experiment will be conducted to verify the influence of soil moisture as a driver of energy fluxes and SA monsoon onset.

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Large-scale atmospheric circulation patterns associated with extreme monsoon precipitation in Pakistan during 1981–2018

Cited by 71 publications

References 71 publications

Spatiotemporal Characteristics and Trend Analysis of Two Evapotranspiration-Based Drought Products and Their Mechanisms in Sub-Saharan Africa

Spatiotemporal Characteristics and Trend Analysis of Two Evapotranspiration-Based Drought Products and Their Mechanisms in Sub-Saharan Africa

Future Changes in Simulated Evapotranspiration across Continental Africa Based on CMIP6 CNRM-CM6

The Empirical Influences of Tibetan Plateau Soil Moisture on South Asian Monsoon Onset

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