Spatial and Temporal Variation of Drought in Far and Mid Western Regions of Nepal: Time Series Analysis (1982-2012)

Kafle, Hemu Kharel

doi:10.3126/njst.v15i2.12118

Cited by 14 publications

(19 citation statements)

References 12 publications

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“…The trend analysis of SPI magnitude showed a decreasing tendency, indicating increasing drought, which is more evident at the longer time scale. Even there is limited study concerning drought trend in Nepal, evidence of increased occurrence of drought due to precipitation deficit is consistent with the results presented by previous researchers (Kafle 2014;Sigdel and Ikeda 2010;Wang et al 2013) Several studies (Chang and Kleopa 1991;Heim 2002;Paulo and Pereira 2006) have shown that precipitation is the main variable determining drought condition; however, many empirical studies (Hu and Willson 2000;Rebetez et al 2006;Vicente-Serrano et al 2009) Nat Hazards (2016) 80:1913-19321927 have shown that rise in temperature has important effects on the severity of droughts conditions. Figure 12 shows that there is increasing trend of temperature in all region of central Nepal in past.…”

Section: Discussionsupporting

confidence: 75%

“…Previous studies in Nepal have focused on the spatial pattern and temporal progression of drought events and its linkages between some climate indices and atmospheric circulation pattern (Kafle 2014;Sigdel and Ikeda 2010;Wang et al 2013), and for annual seasonal periods. There has been no investigation for the period of crop growing seasons.…”

Section: Introductionmentioning

confidence: 99%

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Drought risk assessment in central Nepal: temporal and spatial analysis

et al. 2015

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This paper presents temporal and spatial pattern of drought phenomena in central Nepal using standardized precipitation index (SPI) at multiple time scales. The study is based on 32 years of monthly precipitation data from 40 meteorological stations from 1981 to 2012. Results indicate that, while there is no distinct trend in regional precipitation, interannual variation is large. Trend analysis of drought index shows that most stations are characterized by increases in both severity and frequency of drought and trend is stronger for longer drought time scales. Over the study period, the summer 123Nat Hazards (2016) 80:1913-1932 DOI 10.1007/s11069-015-2055 season of 2004, 2005, 2006, 2009 and winters 2006, 2008 and 2009 were the worst widespread droughts. These dry periods have a serious impact on agriculture-livestock production of central Nepal. Better understanding of these SPI dynamics could help in understanding the characteristics of droughts and also to develop effective mitigation strategies.

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Section: Discussionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Drought risk assessment in central Nepal: temporal and spatial analysis

et al. 2015

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“…Nevertheless, increasing CDD observed over the study area is consistent with the most widespread and worst drought observed in recent decades across the country [99,101,110,111]. Rise in CDD clearly indicates the prolongation of the dry period across the country, implying certain changes in the seasonality of prevailing precipitation regimes [95,96].…”

Section: Dry and Wet Spellssupporting

confidence: 52%

“…Based on the coarse resolution Global Precipitation Climatology Project (GPCP) dataset, Yao et al [113] have also provided evidence of decreasing precipitation over all the Himalayas and an increase in the eastern Pamir regions during 1979-2010. factors besides precipitation. Nevertheless, increasing CDD observed over the study area is consistent with the most widespread and worst drought observed in recent decades across the country [99,101,110,111]. Rise in CDD clearly indicates the prolongation of the dry period across the country, implying certain changes in the seasonality of prevailing precipitation regimes [95,96].…”

Section: Extra Indices (Prcptot Sdii and Wd)supporting

confidence: 52%

Rising Precipitation Extremes across Nepal

Karki

Hasson

Schickhoff

et al. 2017

Climate

198

140

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Abstract:As a mountainous country, Nepal is most susceptible to precipitation extremes and related hazards, including severe floods, landslides and droughts that cause huge losses of life and property, impact the Himalayan environment, and hinder the socioeconomic development of the country. Given that the countrywide assessment of such extremes is still lacking, we present a comprehensive picture of prevailing precipitation extremes observed across Nepal. First, we present the spatial distribution of daily extreme precipitation indices as defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) from 210 stations over the period of . Then, we analyze the temporal changes in the computed extremes from 76 stations, featuring long-term continuous records for the period of 1970-2012, by applying a non-parametric Mann−Kendall test to identify the existence of a trend and Sen's slope method to calculate the true magnitude of this trend. Further, the local trends in precipitation extremes have been tested for their field significance over the distinct physio-geographical regions of Nepal, such as the lowlands, middle mountains and hills and high mountains in the west (WL, WM and WH, respectively), and likewise, in central (CL, CM and CH) and eastern (EL, EM and EH) Nepal. Our results suggest that the spatial patterns of high-intensity precipitation extremes are quite different to that of annual or monsoonal precipitation. Lowlands (Terai and Siwaliks) that feature relatively low precipitation and less wet days (rainy days) are exposed to high-intensity precipitation extremes. Our trend analysis suggests that the pre-monsoonal precipitation is significantly increasing over the lowlands and CH, while monsoonal precipitation is increasing in WM and CH and decreasing in CM, CL and EL. On the other hand, post-monsoonal precipitation is significantly decreasing across all of Nepal while winter precipitation is decreasing only over the WM region. Both high-intensity precipitation extremes and annual precipitation trends feature east−west contrast, suggesting significant increase over the WM and CH region but decrease over the EM and CM regions. Further, a significant positive trend in the number of consecutive dry days but significant negative trend in the number of wet (rainy) days are observed over the whole of Nepal, implying the prolongation of the dry spell across the country. Overall, the intensification of different precipitation indices over distinct parts of the country indicates region-specific risks of floods, landslides and droughts. The presented findings, in combination with population and environmental pressures, can support in devising the adequate region-specific adaptation strategies for different sectors and in improving the livelihood of the rural communities in Nepal.

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“…Nepal droughts over the last 33 years had moderate to extreme drought intensity in Nepal [12]. Drought often occurred in mid and far western Nepal [13], especially during the winter and summer season [14]. The worst widespread droughts in central Nepal were recorded in 2004, 2005, 2006, 2009 in summer and 2006, 2008 and 2009 in winter [15].…”

Section: Introductionmentioning

confidence: 99%

Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015

Baniya

Tang

et al. 2019

Sensors

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Identification of drought is essential for many environmental and agricultural applications. To further understand drought, this study presented spatial and temporal variations of drought based on satellite derived Vegetation Condition Index (VCI) on annual (Jan–Dec), seasonal monsoon (Jun–Nov) and pre-monsoon (Mar–May) scales from 1982–2015 in Nepal. The Vegetation Condition Index (VCI) obtained from NOAA, AVHRR (National Oceanic and Atmospheric Administration, Advanced Very High Resolution Radiometer) and climate data from meteorological stations were used. VCI was used to grade the drought, and the Mann–Kendall test and linear trend analysis were conducted to examine drought trends and the Pearson correlation between VCI and climatic factors (i.e., temperature and precipitation) was also acquired. The results identified that severe drought was identified in 1982, 1984, 1985 and 2000 on all time scales. However, VCI has increased at the rate of 1.14 yr−1 (p = 0.04), 1.31 yr−1 (p = 0.03) and 0.77 yr−1 (p = 0.77) on the annual, seasonal monsoon and pre-monsoon scales, respectively. These increased VCIs indicated decreases in drought. However, spatially, increased trends of drought were also found in some regions in Nepal. For instance, northern areas mainly in the Trans-Himalayan regions identified severe drought. The foothills and the lowlands of Terai (southern Nepal) experienced normal VCI, i.e., no drought. Similarly, the Anomaly Vegetation Condition Index (AVCI) was mostly negative before 2000 which indicated deficient soil moisture. The exceedance probability analysis results on the annual time scale showed that there was a 20% chance of occurring severe drought (VCI ≤ 35%) and a 35% chance of occurring normal drought (35% ≤ VCI ≤ 50%) in Nepal. Drought was also linked with climates in which temperature on the annual and seasonal monsoon scales was significant and positively correlated with VCI. Drought occurrence and trends in Nepal need to be further studied for comprehensive information and understanding.

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Spatial and Temporal Variation of Drought in Far and Mid Western Regions of Nepal: Time Series Analysis (1982-2012)

Cited by 14 publications

References 12 publications

Drought risk assessment in central Nepal: temporal and spatial analysis

Drought risk assessment in central Nepal: temporal and spatial analysis

Rising Precipitation Extremes across Nepal

Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015

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