냉수대지역에서의 Terascan 해수면온도 산출시 구름판별 방법의 오차 완화

Abstract

In this study, a cloud detection method was proposed to mitigate errors occurred when the TeraScan is employed for the sea surface temperature calculation from NOAA/AVHRR data in cold water zone such as upwelling area. With the TeraScan, the cloud detection during day-time and night-time is performed in different ways from one to the other: with the difference between adjacent pixel values using band 2 and band 4 for day-time with the difference between adjacent pixel values using band 3 and band 4 for night-time. With these, a cold water mass might be recognized for a cloud cover and discarded from the calculation simply because it has a strong gradation in its marginal part. With the newly proposed method, finding an optimum threshold through repeated test calculations, the cold water zone which may be excluded from the SST calculation in case of using conventional TeraScan, is to be recognized as water mass and included in the calculation ofSST. The result seems to be very satisfactory for the effective mitigation of errors in cloud detections occurring during SST calculation by TeraScan in cold water zonee cloud detection during day-time and night-time is performed in different ways from one to the other: with the difference between adjacent pixel values using band 2 and band 4 for day-time with the difference between adjacent pixel values using band 3 and band 4 for night-time. With these, a cold water mass might be recognized for a cloud cover and discarded from the calculation simply because it has a strong gradation in its marginal part. With the newly proposed method, finding an optimum threshold through repeated test calculations, the cold water zone which may be excluded from the SST calculation in case of using conventional TeraScan, is to be recognized as water mass and included in the calculation ofSST. The result seems to be very satisfactory for the effective mitigation of errors in cloud detections occurring during SST calculation by TeraScan in cold water zone