Precursor conditions related to Zimbabwe’s summer droughts

Nangombe, Shingirai S.; Madyiwa, Simon; Wang, Jianhong

doi:10.1007/s00704-016-1986-4

Cited by 10 publications

(7 citation statements)

References 64 publications

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“…Such a drying trend is consistent with previous ndings for other parts of southern Africa e.g. (Daron 2014;Morioka et al 2015;Scholes et al 2015) and Zimbabwe in general (Brazier 2015;Makuvaro et al 2017;Nangombe et al 2018). However, while there is generally decreasing total annual precipitation (mean = -0.54mm/annum), this is accompanied by increased precipitation intensity (marked by increasing maximum 1-day precipitation amounts (RX1Day)) over most of the study region.…”

Section: Discussionsupporting

confidence: 92%

Twentieth Century Precipitation Trends in the Upper Mzingwane Sub-catchment of the Northern Limpopo Basin, Zimbabwe

Maviza¹,

Grab

Engelbrecht

2021

Preprint

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This study evaluates precipitation trends in the upper Mzingwane sub-catchment (UMS) of Zimbabwe for the variables of annual precipitation, extremely wet days, consecutive wet days and consecutive dry days. The UMS is of strategic socio-economic significance in terms of its provision of water security and sustenance to livelihoods. The analysis is undertaken at four stations: Bulawayo Goetz, Filabusi, Mbalabala and Matopos National Park, and for the period 1921–2000. In general trends were found not to have local statistical significance, with the exception of the Matopos station (in the westernmost extent of UMS) which records significant increasing (declining) trends for most dryness (wetness) extreme indices. A general north to south-western declining precipitation gradient during the past ~ 69 years over the UMS was also found. The findings provide a baseline for future extended historical and future precipitation trend studies, and are important in the context of the socio-economic impacts of extreme events in this region.

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Section: Discussionsupporting

confidence: 92%

Twentieth Century Precipitation Trends in the Upper Mzingwane Sub-catchment of the Northern Limpopo Basin, Zimbabwe

Maviza¹,

Grab

Engelbrecht

2021

Preprint

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“…This technique has been widely used by many scientists all over the World (Adler et al 2003;Bauer and Del Genio 2006;Thomas and Martin 2007;Nangombe et al 2018). The composite method has been opted to demonstrate the more pronounced patterns of variables and minimize the number of plots associated with the study (Nangombe et al 2018). Drought anomalies were calculated and further processed to create composite drought spatial distribution maps.…”

Section: Composite Analysismentioning

confidence: 99%

“…These meteorological parameters were further subjected to correlation analysis against average JJA rainfall of composite drought years and used to investigate the most correlated parameter and months that could be used as a potential parameter for drought prediction. The geopotential height and wind parameters were investigated at low to middle levels (850,500 and 300 hPa) to assess the depth and strength of convection clouds and circulation systems (Nangombe et al 2018). The main supposition for this study was to identify the prevailing conditions prior to the rainy season to be used as a drought alert to inform all related stakeholders before heading.…”

Section: Correlation Analysesmentioning

confidence: 99%

“…Moreover, it is also observed that the Single Z-Index has picked larger values in both wet and dry conditions. In previous studies, many authors have also compared the robustness of SPI and Single Z-Index and chosen the Single Z-Index (Naresh Kumar et al 2009;Nangombe et al 2018). The main reason is, although the SPI picked out the same drought and wet years but it couldn't pick the severity of wet and dry years as robustly as Single Z-Index.…”

Section: Drought Indices For Isolating Drought Yearsmentioning

confidence: 99%

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Droughts over Pakistan: possible cycles, precursors and associated mechanisms

Hina

Saleem

Arshad

et al. 2021

Geomatics, Natural Hazards and Risk

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In the recent few decades, climate variability had severely affected the socio-economic and environmental conditions worldwide. Frequent shifts in the atmospheric circulation patterns affect large parts of the globe, predominantly the arid and semi-arid regions facing severe to moderate droughts. Therefore, precursors of drought events and their associated mechanisms are important to understand. This study explores the possible cycles and precursor conditions that might be employed for predicting upcoming droughts in Pakistan. Standardize precipitation index and the single Z-index are used to detect and rank the drought years. Moreover, composite analysis is carried out to explore the largescale circulation anomalies related to extreme drought events. Results demonstrate that extreme drought events are highly correlated with wind patterns and intrinsic weather system in the Pacific and Indian Oceans. This study analyzed air temperature, sea level pressure and geopotential height in the average timeperiod of January to March, sea surface temperature from October to December, and wind vectors in March to May as precursors that could be employed to predict the occurrence of droughts in Pakistan. This information is of significance for policymakers to plan climate change adaptive measures accordingly.

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“…Engelbrecht et al (2015) found that temperatures over parts of the subtropics and central tropical Africa have been rising at more than twice the global rate. Both the relatively strong signals of projected climate change in Africa and the relatively low economic developments of Africa increase its vulnerability to the adverse impacts of climate change (Engelbrecht et al 2015;Nangombe et al 2018). Africa is one of the most vulnerable continents due to its high exposure and low adaptive capacity (IPCC 2014).…”

Section: Introductionmentioning

confidence: 99%

Synoptic Features Responsible for Heat Waves in Central Africa, a Region with Strong Multidecadal Trends

Luo

Huang

et al. 2019

Journal of Climate

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Central Africa (CA) is identified as a location of a large positive trend of the occurrence of heat waves (HWs) during 1979–2016, appearing to result mostly from a regime shift around the year 2000. Therefore, we study the evolution of synoptic features associated with the occurrence of HW events in CA. It is found that the HW-related circulation is typically characterized by an anomalous convergence in the upper troposphere but there are important differences for HW events occurring in the south region of CA (CA_S) versus the north region (CA_N). For the occurrence of the HW events in CA_S, the anomalous subsidence associated with upper troposphere anomalous convergence is the dominant factor for their occurrence and magnitude: the strong subsidence leads to warming through greater solar insolation. The HW events in CA_S are also accompanied by an anomalous surface anticyclone in the north with anomalous northerly flow transporting heat into the CA_S region. In contrast, although the HW events in CA_N are also associated with upper troposphere anomalous convergence, the intensity of the convergence is weak with small solar insolation. Instead, the anomalous warm advection is the main factor for determining the magnitude of the HW events in CA_N, induced by the prevailing northerly winds acting on the anomalous temperature gradient. Thus, the synoptic features associated with HW events in the CA_N and CA_S are quite different despite their nearby locations. The discovered dominant factors for the HW events in CA can be used to improve the forecast skill.

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Precursor conditions related to Zimbabwe’s summer droughts

Cited by 10 publications

References 64 publications

Twentieth Century Precipitation Trends in the Upper Mzingwane Sub-catchment of the Northern Limpopo Basin, Zimbabwe

Twentieth Century Precipitation Trends in the Upper Mzingwane Sub-catchment of the Northern Limpopo Basin, Zimbabwe

Droughts over Pakistan: possible cycles, precursors and associated mechanisms

Synoptic Features Responsible for Heat Waves in Central Africa, a Region with Strong Multidecadal Trends

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