Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
415
A preliminary study on NOAA images for non-destructive estimation
of pasture biomass in semi-arid regions of China
Ding Zhi
Institute of Xinjiang Biology, Pedology, and Desert, Academia Sinica, China
Tong Qing-xi, Zheng Lan-fen & Wang Er-he
Airbone Remote Sensing Center, Academia Sinica, China
Xiao Qiang-Uang, Chen Wei-ying & Zhou Ci-song
National Meteorological Bureau, China
ABSTRACT: advanced very nigh reaolution rediometer data from the JMOAA meteorological satellite
have been used to study the vegetation biomass in the Xinjiang regions in China. The major
data from NOAA was aquired with meteorological ground station by the ational meteorological
bureau. For assessment of vegetation biomass the two channels of multispectral data were to
form the Normalized Difference(ND). The spectral bands of these channels were 0.55—0.68 urn,
and 0.725—1.10 um..The Normalized Difference value is very sensitive to the existance vege
tation. The digital processing technique was used for estimation of the relationship between
the Normalized Difference and vegetation biomass production. The ND data of the satellite
images were conpared to field-sampling biomass data. It was found that the relationship bet
ween the two values above was positive and satisfactory. The regression coefficient even ap
proached 0.95. These results show that non-destructive methods for the estimation of the ve
getation is prospective and effective.
This paper, will deal with the principles, methods, and procedures for nOn-destructive esti
mation of pasture biomass with NOAA images. Ideal results have been obtained, and thus fill
in the gaps in the methods of non-destructive estimation pasture biomass in Chica.
1. INTRODUCTION
1.1 Physical geographic conditions in the
test area
The Xinjiang the pasture area has more than
400,000 KM^.The test area is mainly situated
in the Middle and Lower Tarim River Basin,
Xinjiang, and 1ies ( roughly between 40°30'N—
41°30 N, and 83 30 E—87°30 E. The sampling
location lies approximately between 40°30 —
41°30'N, and 84°30'—87°F(Fig.l), and is lo
in the interior Tarim Basin with mountainous
surroundings far from the ocean. It is semi-
arid desert climate in warm temporete zone
with much dry wind, strong vaporation, rare
preciptation, long sunshine and tremendous
temperrature alternation. The annual precip
tation is 25.1—51 mm., and the annual vapo
ration is very high 2,100—2,900 mm..
In this region there are salty-desert typed
soil and central asian desert typed plants,
such as popular diversifolia, phyagmites com
munis, and alhagi pseudoalhagi, etc.
The test area is located in an alluvial p-
lain at the northern margin of the Taklamakan
Desert, and is a representative of arid region
1.2 NOAA satellite
It is a polar orbiting, sun-synchronous, ope
rating satellite in the TIROS-N series of spa
cecraft. NOAA is characterized by high resolu
tion. Images covering the whole world are able
to be received twice a day. NOAA has a view
field of 2,700 km wide, on which the NOAA ad
vanced very high resolution radiometer(AVHRR)
sensor is mounted. The first effective chan-
nel(CHi) is visible red with a wavelength of
0.55—0.68 um, and the second one(CHp) is near
infrared with a wavelength of 0.725--1.10 vim
which are sensitively and directely suitable
for estimation of biomass and the chloropyli
green leaf interaction.(Tal.1) (Townsheng
and Tucker, 1984)
As well known, the Beijing Receiving Sta
tion of NOAA Satellites was built in Beijing
of China in 1983. The center in Beijing has
a circle coverage with a radius of 2,500km.
§nd most of the Chinese territory iscovered,
including the Xinjiang region. The possibi
lities ox orbiting cloud-free imagery are
g reatly enhanced, especially, in the grow
ing season of vegetation.
Four to six orbiting data for one satel
lite can be received in the Beijing Receiv
ing Station of NOAA satellite, due to NOAA’s
polar orbiting, sun synchronous and opera
tional satellite, and NOAA operates with a
coupie, sight or twelve orbits per day cou
ld be obtained. It is svailable for monito
ring changes in pasture biomass and estima
ting crop production to receive one or two
orbiting N0AA?s images, because of the NOAA’s
advantages, and it is also valuable to col
lect whole data from the growing season in
spring to withered season in fall, thus itis
is convenient to observe crop growing situ
ations and their dynamic changes. In addi
tion, if there are several rainfalls, chan
ges in crops with preciptation- may be ob
tained. Simultaneously, no matter during the
day or night, data are effectively received,
and thermo-inertia changes in soil moisture
and water content of plant nay be known and
the dynamic evolution in plant an advanta
geous condition may be monitored. It is un
comparable for MSS, which covers once every
1® day and the cycle duration is too long,
If rainy or cloudy days are encountered,
there is no way to get evident data, and an
other 18 days will be needed to wait, during
which plants may mature, further more, in
that time span, if rain falls again, plants
will grow at atremendous rate, thus there
is no chance to get data on the changes in
plant maturation. As a result, the NOAA is
able to obtain data covering the whole pro-