02183nas a2200133   4500008004100000245009700041210006900138300001500207490000700222520167200229100001501901700001601916856011701932       2003                        eng d00aTemporal responses of NDVI to precipitation and temperature in the central Great Plains, USA0 aTemporal responses of NDVI to precipitation and temperature in t  a2345 -23640 v243 aNormalized Difference Vegetation Index (NDVI) is generally recognized as a good indicator of terrestrial vegetation productivity. Understanding climatic influences, in particular precipitation and temperature, on NDVI enables prediction of productivity changes under different climatic scenarios. We examined temporal responses of remotely sensed NDVI to precipitation and temperature during a nine-year period (1989-97) in Kansas. Biweekly (every two weeks) and monthly precipitation data were derived from 410 weather stations and biweekly temperature data were derived from 17 weather stations inside and around the borders of Kansas. Biweekly and monthly climate maps were derived by interpolation. Biweekly growing season (March-October) NDVI values for Kansas were calculated using National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) NDVI images. Average growing season NDVI values were highly correlated with precipitation received during the current growing season and seven preceding months (15-month duration); biweekly NDVI values were correlated with precipitation received during 2-4 preceding biweekly periods; and response time of NDVI to a major precipitation event was typical 1-2 biweekly periods (2-4 weeks). Temperature was positively correlated with NDVI early and late in the growing season, and there was a weak negative correlation between temperature and NDVI in the mid growing season. Precipitation has the primary influence on NDVI and, by inference, on productivity. The relationship between precipitation and NDVI is strong and predictable when viewed at the appropriate spatial scale.1 aWang, J.R.1 aPrice, K.P.  uhttp://lter.konza.ksu.edu/content/temporal-responses-ndvi-precipitation-and-temperature-central-great-plains-usa00514nas a2200145   4500008004100000245007100041210006900112300001300181490000700194100001500201700001900216700001600235700001700251856010000268       1989                        eng d00aMapping surface soil moisture with L-band radiometric measurements0 aMapping surface soil moisture with Lband radiometric measurement  a305 -3120 v271 aWang, J.R.1 aSchmugge, T.J.1 aShiue, J.C.1 aEngman, E.T.  uhttp://lter.konza.ksu.edu/content/mapping-surface-soil-moisture-l-band-radiometric-measurements01661nas a2200145   4500008004100000245009200041210006900133300001300202490000700215520113300222100001901355700001501374700001601389856011001405       1988                        eng d00aResults from the push broom microwave radiometer flights over the Konza Prairie in 19850 aResults from the push broom microwave radiometer flights over th  a590 -5960 v263 a<p>There were four flights of the NASA C-130 aircraft carrying the Push Broom Microwave Radiometer (PBMR) over the Konza Prairie Research Natural Area in eastern Kansas in 1985. Their objective was to observe surface soil moisture variations with the PBMR. The radiometer operates at the 21-cm wavelength and has four beams that sweep out a swath of about 1.2 times the aircraft altitude. The resolution of each beam is 0.3 times the altitude. At the time of the flights the soil conditions ranged from very wet to moist and the microwave emission expressed as brightness temperatures for the burned watersheds ranged from below 200 to about 245 K. The brightness temperatures were correlated (r2 = 0.5) with surface moisture measurements and the slope of the regression is in good agreement with prior results over other grasslands. However, for the unburned watersheds the brightness temperatures were around 270 K and roughly independent of the soil moisture conditions. In these unburned watersheds, a buildup of a thatch layer serves as highly emissive layer above the soil, causing high brightness, especially when wet</p>1 aSchmugge, T.J.1 aWang, J.R.1 aAsrar, G.A.  uhttp://lter.konza.ksu.edu/content/results-push-broom-microwave-radiometer-flights-over-konza-prairie-198501771nas a2200145   4500008004100000245009100041210006900132260001800201300001300219520123100232100001901463700001501482700001901497856010901516       1987                        eng d00aResults from the pushbroom microwave radiometer flights over the Konza Prairie in 19850 aResults from the pushbroom microwave radiometer flights over the  aAnn Arbor, MI  a877 -8813 a<p>There were 4 flights in 1985 of the NASA C-130 aircraft carrying the Push Broom Microwave Radiometer (PBMR). The flights were over the Konza Prairie in central Kansas and their objective was to observe surface soil moisture variations with the PBMR. The radiometer operates at the 21-cm wavelength which is most sensitive to soil moisture. It has 4 beams which sweep out a swath of about 1.2 times the aircraft altitude. The resolution of each beam is 0.3 time the altitude. At the time of the flights the soil conditions ranged from very wet to moist and the brightness temperatures for the burned watersheds ranged from below 200 K to about 230 K. These results were well correlated (r2 = 0.7) with ground truth measurements and in good agreement with prior results over pasture grass situations. However for the unburned watersheds the brightness temperatures were around 270 K and roughly independent of the soil moisture conditions. In these unburned watersheds there is a buildup of a thatch layer which serves as highly emissive layer above the soil, especially when wet. This layer also caused a lower return to be observed over this area during this period, which is consistent with the radiometer observations</p>1 aSchmugge, T.J.1 aWang, J.R.1 aLawrence, R.W.  uhttp://lter.konza.ksu.edu/content/results-pushbroom-microwave-radiometer-flights-over-konza-prairie-1985