Surface Temperatrue Retrieval from Satellite Data Over South China sea
Shattri, B.Manosr, Quazi Halid Hasan, Abd Rehman Ramli
Faculty of Engineering
University Putra Malaysia
43400 UPM Serdang, Seldang , Selangor, Malaysia
Tel : 609-6175135; Fax: 609-6175136
E-mail:shattri@rs.eng.upm.edu.my
abstract
NOAA AVHRR data is widely used in monitoring and manager of natural resources specifically oceanographic features from space. a near real time observation and management system has been developed utilizing remotely sensed data.
For geocoding of ht satellite images, an orbital model has been used of relating the geographic position ( latitude/longitude ) with the image elements ( row/column ). The retrieval of sea surface temperature from NOAA data is the most improvement object for the above mentioned objectives. The algorithms based on radioactive transfer equations was used to extract sea surface temperature. Two model s namely I) single channel and ii) split window approach are developed and the coefficients of the models can be obtained from radiosonde data. For split window approach, AVHRR channel 4 & 5 data has been used. The comparison between the estimated SST and ground data over south China sea are discussed. The developed models was customized in EAST environment and can used for fish forecasting and monitoring of oil spill over Malaysian sea water.
Introduction
Satellite images navigation is a task of locating latitude/longitude with any point interms of line/row in the image. for the image navigation, many researchers ( Brush, 1988; Ho and Assem, 1986; Emery et al., 1989) pointed out a number of model with different approaches. Actually the Earth is not perfect sphere but elliptical with a small degree of eccentricity and spherical Earth shape can be used to avoid more complexity and to get accuracy in the orbital modeling (Illera et al., 1996).
In the past , a number of irradiative transfer models have been developed to correct for the effect of atmospheric attenuation on remotely-sensed data. A larger amount of work as already been undertaken and successful results have been obtained using three methods, namely a single infrared channel method ( Djavadi and Anderson, 1987), a multi-channel ( split window ) method ( Parabhakara et al., 1974) and a multi-angel method ( hoyler, 1984).
The objective of this study is to develop near real time system for fish forecasting and monitoring of oil spill. The uncertainty of he proposed physical model of orbital navigation and the measurement of sea surface temperature are determined to fulfill the objectives. Finally, the use of the model for georeferencing of the image and estimate sea surface temperature over south China sea is presented.
Modeling approaches
Orbit model
Fig .1, represents the orbital model. Here the assumption is the spherical earth and circular satellite orbit. The relation in between geographical position ( latitude/longitude ) and coordinates of the acquired image ( line/pixel ) is as (10.
Fig 1. satellite orbit geometry : I, hs g, d, le, ld., fD., Xo, Yo are inclination, height azimuth angle, off-nadir view angle, equator crossing longitude, longitude reference to ascending node, latitude reference to ascending node and image dimension respectively.
L=F(l ,f) and P =f (l ,f) (1)
This model was described by Ho and Assem ( 1986) and successfully implemented by many researchers ( Emery et al., 1989.; Illera et al., 1996).
The equator crossing longitude and the time interval are calculated using geographic coordinates and measured in the images from a control point [8]. The satellite inclination, height, scan start time can be found from satellite operational agencies and header of the image file respectively.
