Spatial patterns of NDVI in response to precipitation and temperature in the central Great Plains

The Normalized Difference Vegetation Index (NDVI) has proven to be a robust indicator of terrestrial vegetation productivity. Among climatic factors, precipitation and temperature strongly influence both temporal and spatial patterns of NDVI. We examined spatial responses of NDVI to precipitation and temperature during a 9-year period (1989-1997) in Kansas. Biweekly climate maps ( precipitation and temperature) were constructed by interpolation of weather station measurements. Maps of biweekly growing season (March to October) NDVI were constructed for Kansas using National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) NDVI images. Average precipitation is a strong predictor of the major east-west NDVI gradient. Deviation from average precipitation explained most of the year-to-year variation in spatial patterns. NDVI and precipitation covaried in the same direction (both positive or both negative) for 60-95% of the total land area. Minimum and average temperatures were positively correlated with NDVI, but temperature deviation from average was generally not correlated with NDVI deviation from average. Our results demonstrate that precipitation is a strong predictor of regional spatial patterns of NDVI and, by inference, patterns of productivity.