摘要:

This paper describes how NOVI responds to daily precipitation for vegetation under water-limited growth conditions (e.g., in arid or semi-arid environments). An analytical model was developed to address timing to peak NOVI response and total duration of NOVI response to a rainfall event with the passage of time. The model also describes how effectively the vegetation uses precipitated water. A case study in the Sandhills area of Nebraska, with NOVI calculated from Landsat-MSS images, showed that the model can accurately portray NOVI time series, and then can be used to derive some useful information about relations of NOVI and precipitation. For the vegetation in the test area, we found that the peak vegetative response to a precipitation event shifts from about 14 days after the rainfall event at the beginning of a growing season to 25 days at the late stage of the season, and then shifts back to 12 days at the end of the season. The duration of response, similar to the peak response in behavior, is 22, 61, and 25 days, respectively.

ISSN:0143-1161    

DOI:10.1080/01431169408954231

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Two different approaches to relate wheat yield with spectral indices derived from remotely-sensed data have been explored for the state of Punjab, India. In the study based on site-level approach yield obtained from crop-cutting sites was found to be linearly related to NIR/Red ratio derived from Landsat MSS data of corresponding sites in Ludhiana and Patiala districts of Punjab. Incorporation of agrometeorological data was also tried. Certain inherent limitations of the site-level approach led to the district-level studies which focused on the relation of district yields with corresponding average spectral indices derived from satellite sensors like Landsat MSS and lRS-LISS-i. Significant correlations were observed in all cases and the relation based on Landsat MSS/IRS LISS-I data was used for trial forecast of wheat yields for 1989–90 season. A comparison of remote-sensing based production forecast showed good agreement with the conventional estimate of Bureau of Economics and Statistics at state level although at district level, deviations were larger.

ISSN:0143-1161    

DOI:10.1080/01431169408954232

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This Letter describes an example of classification of a SPOT HRV sub-scene of the urban region of Sherbrooke, Quebec, Canada. The radiometric information of the three multispectral bands as wellas the textural characteristics derived from the panchromatic band are used in the classification process. A more accurate classification is obtained by combining the multispectral and the textural analysis.

ISSN:0143-1161    

DOI:10.1080/01431169408954233

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor