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NOAA-AVHRR FOR CROP CONDITION MONITORING 
R.J. Brown, M. Bernier 
Canada Centre for Remote Sensing 
G. Fedosejevs, L. Skretkowicz 
Intera Environmental Consultants 
‘It has been shown that LANDSAT multispectral scanner (MSS) 
data can be effectively used to monitor crop condition but the 
timely acquisition of the data can be a problem. The Advanced Very 
High Resolution Radiometer (AVHRR) on board the National Oceanic and 
Atmospheric Administration (NOAA)-6 and subsequent satellites appears. 
to be a complimentary sensor to the MSS which can alleviate this 
timeliness of data acquisition problem. The AVHRR with its wide swath 
width can give daily synoptic coverage of any agricultural area. These 
data can be used to diréct the analysis of the higher resolution 
LANDSAT imagery. The question that must be answered for this to occur 
is whether the low resolution AVHRR data can supply reliable crop 
condition information. This paper will report upon our study to use 
the AVHRR to determine crop condition. 
With a resolution of 1.1 km at nadir the sensor does not 
image individual fields but rather gives information about a general 
area. This area reflectance depends upon the mix of ground cover and 
particularly the amount of summerfallow present. Corrections to the 
radiance data have been made for the amount of summerfallow present 
and for topographical features such as slope and surface roughness 
(changes in slope). The results of this analysis will be presented 
along with what geometric and radiometric corrections are made to the 
data. A data set consisted of: 
(i) NOAA-6 AVHRR imagery for every clear day over 
Saskatchewan, Canada in 1981 from May 23 
until August 31 (approx. 20 days). 
(ii) NOAA-7 AVHRR imagery for selected days over 
Saskatchewan, from July 9, 1981 to August 15, 
1981 (approx. 7 days). 
(iii) LANDSAT multispectral scanner imagery for 
three areas in Saskatchewan from 1977 until 
1981. : 
We are pleased with the results to date and it appears that 
NOAA-AVHRR data may become an important data source for vegetation 
studies. 
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