摘要:

Although the practice of remote sensing depends upon the use of accurate field observations, collection of field data remains one of the least systematized aspects of the field. This paper presents a detailed description of the field data collection strategy employed for our study of agricultural land uses in Rondonia, Brazil. Key elements of our approach include: careful positioning of sample areas, multi-image analysis, imagery over several dates, use of video imagery, systematic collection of ground photographs, preparation of detailed maps and field sketches. Field data were carefully examined in the context of these several sources of information, and evaluated to assure that interpretations are consistent with the several sources of data.

ISSN:0143-1161    

DOI:10.1080/01431169508954399

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The Bangladesh cyclone of 15–22 November 1992 was observed by the scatterometer onboard the ERS-1 satellite. The unique data set from this scatterometer (which is the first of its kind over an Indian Ocean cyclone) has been analysed in order to study various features of the cyclone. A new technique to estimate the centre of the cyclone objectively from the observed winds has been proposed. Based on the precise knowledge of the centre, the directional ambiguity of the wind data has been removed.

ISSN:0143-1161    

DOI:10.1080/01431169508954400

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Central wavenumber values for the thermal channels of the Advanced Very High Resolution Radiometer/2 (AVHRR/2) sensor onboard the NOAA-II satellite have been re-evaluated. The NOAA-11 AVHRR/2 central wavenumber values were incorrectly specified on the launch of the satellite (Planet 1988) and in the subsequent editions of theNOAA Polar Orbiter Data Users Guide(Kidwell 1991 a, b). This Letter lists the correct values of the NOAA-11 AVHRR/2 central wavenumbers and details the differences that use of these corrected values makes to estimates of derived brightness temperature. Resultant changes in channel 3 and 4 brightness temperature are found to be insignificant but channel 5 brightness temperatures are 0.34–0.44degK higher than those calculated with the incorrect central wavenumbers. Updating the central wavenumbers is shown to cause ‘split window’ sea surface temperature estimates to decrease by 0.6–1.7 degK whereas ‘triple-window’ estimates generally decrease by 0.34–0.42 degK.

ISSN:0143-1161    

DOI:10.1080/01431169508954401

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

One of the simplest systems a limnologist can study is the periodical variations in areal extent of lakes. This system may be represented in a single difference equation Xt+1, =λX1(1 — Xt). Based on this equation, logistic maps have been constructed to predict the size of changing areal extent of water and marsh in the Chilka lake.

ISSN:0143-1161    

DOI:10.1080/01431169508954402

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The effect of biogenic crust on imagery acquired by spaceborne sensors is demonstrated. The crust consists mostly of microphytes such as cyanobacteria. The macrophytes (higher vegetation) on the sand dunes are sparse and have a relatively low spectra! reflectance response. However, since a considerable ponton of the ground is covered by this biogenic crust, (which has a different spectral reflectance from that of the mobile sands), a sharp brightness contrast is created between the two areas. It can be concluded that the well-known contrast between Sinai (Egypt) and the Negev (Israel), that has long drawn the attention of many observers, is not a direct result of vegetation cover but is caused by an almost complete cover of biogenic crust in the Negev, and a lack of this crust in Sinai, due largely to man's activities.

ISSN:0143-1161    

DOI:10.1080/01431169508954403

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The need for information on spectral ozone transmittance arises from the temperature-dependence of the ozone absorption coefficients in Hartley-Huggins bands (200–360 nm). The methodological approach reported here employs the convolution between vertical profiles of ozone and temperature to determine the ozone layer's effective temperature. Introducing temperature makes it possible better to approximate UV-spectral ozone transmittance values computed by LOWTRAN-7.

ISSN:0143-1161    

DOI:10.1080/01431169508954404

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The Global Resource Information Database—a part of the United Nations Environment Programme—conducts a bi-annual survey of geographical information system (GIS) and image processing (IP) software. This survey makes information about software products available in developing countries. The 1993 survey showed that the number of installations of GIS, IP, and related software products increased dramatically from 1991 to 1993, mostly in North America and Europe.

ISSN:0143-1161    

DOI:10.1080/01431169508954405

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This Letter presents preliminary observations made with the ERS-1 wind scatterometer over land surfaces. A global backscattering coefficient image, synthesized from the original raw data indicates a strong correlation between the radar signal and the distribution of the main vegetation types throughout the world. In particular, tropical vegetation formations are well identified. The effects of angular and multitemporal variations on the backscattering coefficient σ0are shown for different terrestrial surfaces. Illustrations are given for the African continent which presents numerous vegetation types along a north-south latitudinal gradient. Results indicate the strong capability of the ERS-1 scatterometer to discriminate and monitor vegetation change at a global scale.

ISSN:0143-1161    

DOI:10.1080/01431169508954406

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Passive microwave images of Antarctica from the Special Sensor Microwave Imager (SSM/I) are used to track two giant tabular icebergs that originated from the Larsen ice shelf in 1986. Since microwave radiation is relatively insensitive to weather and unaffected by lighting conditions, the SSM/I instrument provides all-weather, year-round viewing. The icebergs are visible almost every day giving an ideal temporal resolution for tracking their motion. One of the icebergs was tracked until October 1988, six months after its last position noted in the Navy/NOAA Joint Ice Centre ice charts. The tracks of both icebergs reveal motion in sympathy with observed oceanographic currents and eddies.

ISSN:0143-1161    

DOI:10.1080/01431169508954407

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor