Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015
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...
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MDPI AG
2019-01-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/19/2/430 |
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| author | Binod Baniya Qiuhong Tang Ximeng Xu Gebremedhin Gebremeskel Haile Gyan Chhipi-Shrestha |
| author_facet | Binod Baniya Qiuhong Tang Ximeng Xu Gebremedhin Gebremeskel Haile Gyan Chhipi-Shrestha |
| author_sort | Binod Baniya |
| collection | DOAJ |
| description | 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<sup>−1</sup> (<i>p</i> = 0.04), 1.31 yr<sup>−1</sup> (<i>p</i> = 0.03) and 0.77 yr<sup>−1</sup> (<i>p</i> = 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. |
| first_indexed | 2024-04-12T05:44:47Z |
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| id | doaj.art-f3a3a372c9c7454c829526b22d83f591 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-04-12T05:44:47Z |
| publishDate | 2019-01-01 |
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| spelling | doaj.art-f3a3a372c9c7454c829526b22d83f5912022-12-22T03:45:29ZengMDPI AGSensors1424-82202019-01-0119243010.3390/s19020430s19020430Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015Binod Baniya0Qiuhong Tang1Ximeng Xu2Gebremedhin Gebremeskel Haile3Gyan Chhipi-Shrestha4Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaKey Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaKey Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaKey Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaÉcole Supérieure d’Amenagement du Territoire, Université Laval, 1628 Pavillon Savard, Université Laval, Québec City, QC G1K7P4, CanadaIdentification 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<sup>−1</sup> (<i>p</i> = 0.04), 1.31 yr<sup>−1</sup> (<i>p</i> = 0.03) and 0.77 yr<sup>−1</sup> (<i>p</i> = 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.https://www.mdpi.com/1424-8220/19/2/430VCIdroughtexceedance probabilityclimateNepal |
| spellingShingle | Binod Baniya Qiuhong Tang Ximeng Xu Gebremedhin Gebremeskel Haile Gyan Chhipi-Shrestha Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015 Sensors VCI drought exceedance probability climate Nepal |
| title | Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015 |
| title_full | Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015 |
| title_fullStr | Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015 |
| title_full_unstemmed | Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015 |
| title_short | Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015 |
| title_sort | spatial and temporal variation of drought based on satellite derived vegetation condition index in nepal from 1982 2015 |
| topic | VCI drought exceedance probability climate Nepal |
| url | https://www.mdpi.com/1424-8220/19/2/430 |
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