Surthce elevation is tile basic data for geo-science. It is difficult to retrieve tidal-flats＇ elevation from a single Re- mote Sensing （RS） image because of the complicated sediment dynanical environment and huge ...Surthce elevation is tile basic data for geo-science. It is difficult to retrieve tidal-flats＇ elevation from a single Re- mote Sensing （RS） image because of the complicated sediment dynanical environment and huge spatial difference in tidal-flats＇ moisture content. A Digital Elevation Model （DEM） construction method for inconstant inter-tidal zone based on high tempo-resolution MODIS data set in a short period is proposed in a ease study on the Dongsha Sandbank of the Jiangsu Radial Tidal Sand-ridges. In the present study, a batch-preprocessing method based on image partition to handle massive MODIS IB images is developed and applied to 8163 scenes of MODIS images. The dataset of short-period and muhi-temporal MODIS images for inter-tidal flats＇ DEM inversion is selected and the usability of MODIS dataset is analyzed. Shorelines of the Dongsha Sandbank are extracted by use of batch supervised classification. In accord with tidal- 0 level forecasted by the Chenjiawu Tidal Gauge Station at the overpass moment of each RS image, DEMs of inter-tidal flats in January and sutmner（Jul, Aug and Sept）, 2003 are built under ArcG1S9.2. Studies show that： （1） The dataset of short-duration and muhi-phase MODIS images can be used to retrieve the historical DEM of tidal-flats at changeful tidal flats. （2） Aualysis on usability of MODIS images from Aqua and Terra indicates that there are more usable and higbquality MODIS images in spring, autumn and winter, but less in summer. Therefore, the period for building inter-tidal fiats＇ DEM is suggested to be one month in spring, autumn and winter and three months in summer.展开更多
Temperature structure parameter in the vertical is estimated once by using the turbulence outer scale approximation and another by using the Obukhov similarity relationship during the formation of an elevated inversio...Temperature structure parameter in the vertical is estimated once by using the turbulence outer scale approximation and another by using the Obukhov similarity relationship during the formation of an elevated inversion.A comparison of the profiles drawn using both the methods is done for the pur- pose of assessing the accuracy of the similarity method when applied to levels above the surface-based layer.The profiles obtained by both the methods are also compared with a similar profile obtained af- ter considering a bulk shear between the ground and top of the elevated layer.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos .40701117 andJ0630535)
文摘Surthce elevation is tile basic data for geo-science. It is difficult to retrieve tidal-flats＇ elevation from a single Re- mote Sensing （RS） image because of the complicated sediment dynanical environment and huge spatial difference in tidal-flats＇ moisture content. A Digital Elevation Model （DEM） construction method for inconstant inter-tidal zone based on high tempo-resolution MODIS data set in a short period is proposed in a ease study on the Dongsha Sandbank of the Jiangsu Radial Tidal Sand-ridges. In the present study, a batch-preprocessing method based on image partition to handle massive MODIS IB images is developed and applied to 8163 scenes of MODIS images. The dataset of short-period and muhi-temporal MODIS images for inter-tidal flats＇ DEM inversion is selected and the usability of MODIS dataset is analyzed. Shorelines of the Dongsha Sandbank are extracted by use of batch supervised classification. In accord with tidal- 0 level forecasted by the Chenjiawu Tidal Gauge Station at the overpass moment of each RS image, DEMs of inter-tidal flats in January and sutmner（Jul, Aug and Sept）, 2003 are built under ArcG1S9.2. Studies show that： （1） The dataset of short-duration and muhi-phase MODIS images can be used to retrieve the historical DEM of tidal-flats at changeful tidal flats. （2） Aualysis on usability of MODIS images from Aqua and Terra indicates that there are more usable and higbquality MODIS images in spring, autumn and winter, but less in summer. Therefore, the period for building inter-tidal fiats＇ DEM is suggested to be one month in spring, autumn and winter and three months in summer.
文摘Temperature structure parameter in the vertical is estimated once by using the turbulence outer scale approximation and another by using the Obukhov similarity relationship during the formation of an elevated inversion.A comparison of the profiles drawn using both the methods is done for the pur- pose of assessing the accuracy of the similarity method when applied to levels above the surface-based layer.The profiles obtained by both the methods are also compared with a similar profile obtained af- ter considering a bulk shear between the ground and top of the elevated layer.
