Beijing-1 small satellite has three bands of green, red and
near-infrared, with spatial resolution of 32 meters. Three days
Beijing-1 data are used to retrieve distribution and living status of Enteromorpha clathrata (a kind of green algae and
called Hutai in Chinese). First, use the non-supervised classification to separate the kinds who has big spectral
differences. Second, the cloud and cloud-covered green algae can be separated by the ratio of near-infrared and red. In
the end, the green algae distribution is obtained. The NDVI is used for indicator of living status and density.
MODIS has the advantage of high temporal although its spatial resolution is much coarse than Beijing-1. A decision tree
is developed to retrieve green algae. First, the cloud is eliminated by its high reflectance. Second, the NDVI is calculated
and a threshold value is set to determine whether the grid is green algae.
The green algae distribution results from Beijing-1 and MODIS are compared. Generally, the Beijing-1 extracted green
algae is coincide with the MODIS extracted green algae. The Beijing-1 extracted algae area is smaller than that of
MODIS, because the MODIS has spatial resolution of 250-meter, its situation of mix pixel is severer.
Multi-temporal series of satellite SPOT-VEGETATION Normalized Difference Vegetation Index (NDVI) has long
time-series from 1998 to present. The convenient downloading policy make those data can be widely used all through the
world. The data is used for global vegetation monitoring and variation analysis. The spring onset date reflects the
vegetation growth and its feedback to climate and human activity, and become an important variable for the global
climatic change and production monitoring. In this paper, the spatial spring onset date information in south and central
China is portrayed, and the spring onset frequency distribution map is sketched by using the multi-year 10-days
composite SPOT/VGT NDVI data. First, the long time series NDVI is reconstructed. Then a relative threshold value
method is given to determine whether the vegetation begins to resuscitate. The spring onset frequency map mainly
parallels the latitude. But because of the heterogeneity of vegetation and monsoon, the spring onset movements do not
parallel the latitude completely.
By analyzing several collocated QuikSCAT measurements and Special Sensor Microwave Imager (SSM/I) rain rate in
typhoons, the evidence of rain influence to wind retrieval is presented. The results show that the present of heavy rain in
typhoons will cause large bias in both wind speed and wind direction for QuikSCAT wind retrieval. So that the
Holland's model is applied in the ambiguity clear process to correct the errors in wind direction induced by rain. Also, a
radiate transfer function (RTF) and collocated SSM/I rain rate is employed to correct the attenuation and scattering
effects of rain. The performance of RTF method is limited due to lack of information of the collocated rain rate and the
un-precise of the RTF. As an alternative way to RTF, an interpolation method which just uses the data from QuikSCAT
itself is introduced to correct the attenuation and scattering effects of rain. This method is applied to retrieve the wind
vector in typhoon Ioke, the result shows that the bias in the wind direction and wind speed induced by rain has both been
well corrected, indicating that our correction to the impacts of rain on QuikSCAT wind retrieval in typhoons is effective.
Because of global climatic variations and anthropogenic influence on local environment, as the active interaction belt
between ocean and land, the coastal ecosystems are sensitive even part of them are under pressure. It is of very necessary
to diagnose whether they are in healthy stage. The Zhejiang coastal zone situated at about 120°E-123°E and 27°N-31°N, the landuse have changed largely during the past 20 years as long as the rapid economic development. In this
paper the largest island-Zhoushan island- in the Zhejiang coastal line is selected as the study site. The objective is to
establish a way to assess coastal ecosystem health stage. Indicators include the landuse transformation, water quality,
ecosystem services during 1986 to 2005. The results indicate that the human pressure become more and more large. The
scene generally is the outcome of economic pursuing activity. In the discussion we also provide some strategy to keep
the human and nature harmonious.
With the availability of scatterometer data, surface wind vectors can be estimated from the backscatter measurement over
oceans, guarantee global, long-term monitoring of the winds on the oceans, which make them very valuable for climate
studies and other applications. At moderate wind speeds, the wind speed derived by scatterometer is considered reliable.
But at higher wind speeds, scatterometers appear to underestimate the wind speed, especially in tropical cyclones,
because of deficiencies of the geophysical model function for high winds, attenuation caused by rain, influence of wind
gradient, and the saturation of the backscattering under high wind.
As a passive microwave sensor, radiometer does not show obvious saturation phenomena under high wind, therefore it is
an appropriate candidate to be used to retrieve high wind speed. In this paper, combined scatterometer and radiometer
data is used to retrieve wind field under high wind condition. Using in situ data and meteorological data as a criterion,
we compared the wind retrieval performances of scatterometer and radiometer. Results show that it is better to use
radiometer data as a replacement of scatterometer while observing high wind speed.