Droughts of the Late 1980s in the United States as Derived from NOAA Polar-Orbiting Satellite Data

Abstract

Drought is one of the most adverse and powerful weatherrelated disasters that occur every year across a portion of the United States. The consequences of droughts quite often can be devastating. To mitigate these consequences, droughts require careful monitoring. Recently, NOAA's National Environmental Satellite Data and Information Service developed a new Advanced Very High Resolution Radiometer-based vegetation condition index (VCI) that showed good results when it was used for drought detection and tracking. The VCI is a vegetation index with reduced noise and is adjusted for land climate, ecology, and weather conditions. This index provides a quantitative estimate of weather impact on vegetation and also measures vegetation conditions. Several large-area experiments showed that the VCI had excellent ability to detect drought and to measure the time of its onset and its intensity, duration, and impact on vegetation. The VCI provides accurate drought information not only for the cases with welldefined, prolonged, widespread, and very strong droughts, but also for very localized, short-term, and ill-defined droughts. The advantages of this index compared to conventional ground data are in providing more comprehensive, timely, and accurate drought information. This paper describes the methodology and technical principles used to derive the vegetation condition index, explores data processing, and gives many examples of VCI application for drought monitoring in the United States during 1985-90. The spatial and temporal patterns of VCI-derived drought were in a very good agreement with the identical patterns identified from precipitation and yield anomalies.

Towards an integrated soil moisture drought monitor for East Africa

“…In the US, these include the Vegetation Drought Response Index (Veg-DRI), which monitors drought conditions for the continental US by combining climate-related variables with satellitederived vegetation condition information obtained using Advanced Very High Resolution Radiometer (AVHRR)-based vegetation indices (Brown, 2010), and the University of Washington Experimental Surface Water Monitor , based on a multi-model monitor employing VIC (Liang et al, 1994), Sacramento Soil Moisture Accounting (SAC-SMA; Burnash, 1995), Community Land Model (CLM; Dai et al, 2003;Lawrence et al, 2011), Catchment (Koster et al, 2000), and Noah (Chen et al, 1996;Ek et al, 2003;Koren et al, 1999) land-surface models (LSMs). Other AVHRR-derived drought indices include the Vegetation Condition Index (VCI), derived from AVHRR Normalized Difference Vegetation Index (NDVI) data and the Temperature Condition Index (TCI), which is calculated using AVHRR thermal data (Kogan, 1990(Kogan, , 1995, as well as the Vegetation Health Index (VHI) which combines the VCI and TCI (Kogan, 1997). Remotely sensed land-surface temperature and vegetation cover information have also been combined within the Atmosphere-Land Exchange Inverse (ALEXI) surface energy balance algorithm (Anderson et al, 1997(Anderson et al, , 2007a to generate an Evaporative Stress Index (ESI), quantifying anomalies in the ratio of actual to potential evapotranspiration (Anderson et al, 2011a,b).…”

Determining the start, duration, and strength of flood and drought with daily precipitation: Rationale

“…In addition to precipitation, the PDSI also needs to use temperature and other local hydrological quantities. It has been found that the PDSI has many significant limitations [e.g., Alley, 1984;Karl and Knight, 1985;Smith et al, 1993;Willeke et al, 1994;Kogan, 1995;McKee et al, 1995;Guttman, 1998] and is not satisfied in the operational monitoring [e.g., Hayes et al, 1999]. Mo and Chelliah [2006] made some modifications to improve the PDSI.…”

Vegetation condition index pattern (2002-2007) over Indian agro-climate regions, using of GIS and SPOT sensor NDVI data

“…(2) At 100 percent VCI, NDVI j = NDVI max and at zero per cent VCI, NDVI j = NDVI min . According to Kogan (1997), different degrees of drought severity are indicated by VCI below 50 per cent and VCI of 35 per cent is a threshold for extreme drought (Table 3). Based on this the VCI values obtained were reclassified into drought severity as: 50 per cent to 100 per cent, normal to above normal condition (wet); < 50 per cent to 35 per cent, moderate drought; < 35 to 20 per cent severe drought; < 20 per cent to zero per cent very severe drought.…”