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1.
Abstract

As a key component of digital earth, remotely sensed data provides the compelling evidence that the amount of water vapour transferred from the entire global surface to the atmosphere increased from 1984 to 2007. The validation results from the earlier evapotranspiration (ET) estimation algorithm based on net radiation (R n ), Normalised Difference Vegetation Index (NDVI), air temperature and diurnal air temperature range (DTaR) showed good agreement between estimated monthly ET and ground-measured ET from 20 flux towers. Our analysis indicates that the estimated actual ET has increased on average over the entire global land surface except for Antarctica during 1984–2007. However, this increasing trend disappears after 2000 and the reason may be that the decline in net radiation and NDVI during this period depleted surface soil moisture. Moreover, the good correspondence between the precipitation trend and the change in ET in arid and semi-arid regions indicated that surface moisture linked to precipitation affects ET. The input parameters R n , T air, NDVI and DTaR show substantial spatio-temporal variability that is almost consistent with that of actual ET from 1984 to 2007 and contribute most significantly to the variation in actual ET.  相似文献   

2.
A method is proposed for the calculation, based on the Goudriaan model, of estimates of various combinations of spectral radiance coefficients Pi which are optimal for interpretation of soil color and moisture, vegetation cover density, above-ground reserves of phytomass, and color and orientation of phytoelements. These estimates correspond rather closely with actual measurements obtained from the field. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1986, No. 4, pp. 75-79.  相似文献   

3.
The author outlines a method for extrapolating reference spectral data describing the condition of certain crops obtained for a particular point in time to periods for which reliable remote sensing data are not available. Examination of the correspondence between crop “condition classes,” identified through visual interpretation of aerial imagery, and actual yields/biomass for a number of phases of crop development of winter wheat for several crop years provides basic information for a probability matrix of the condition of a crop at times B, C, and D based on previous conditions at times A, B, and C. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1988, No. 4, pp. 73-79.  相似文献   

4.
The authors derived the normalized difference vegetation index (NDVI) from the NOAA/AVHRR Land dataset, at a spatial resolution of 8km and 15-day intervals, to investigate the vegetation variations in China during the period from 1982 to 2001. Then, GIS is used to examine the relationship between precipitation and the Normalized Difference Vegetation Index (NDVI) in China, and the value of NDVI is taken as a tool for drought monitoring. The results showed that in the study period, China’s vegetation cover h...  相似文献   

5.
The findings of a program monitoring the growth of an enormous man-made lake, created by the flooding of a low-lying area by irrigation water drainage, are described. Black-and-white space images for the period 1973-1985 are used to determine rates of shoreline displacement, map the growth in the lake's water area, and to determine probable areas of future flooding as a basis for prediction of future lake levels and shoreline positions. Translated from: Geodeziya i kartografiya, 1988, No. 7, pp. 44-46.  相似文献   

6.
The World Atlas of Snow and Ice Resources, scheduled for publication in the late 1980s, is an extensive cartographic summary of current knowledge about snow and ice. Roughly 750 maps organized under 17 broad themes cover topics such as glacier morphology, temperature and precipitation conditions in glacier formation, avalanches, meltwater runoff, sea ice, and past glaciation. The organization of the project is described along with the contents of major thematic sections, and examples of the use of basic initial maps to validate information used in more complex derivative maps are provided. Translated from: Materialy glyatsiologicheskikh issledovaniy, USSR Geophysical Committee Publication No. 51. Moscow: Mezhvedomstvenniy geofizicheskiy komitet, 1984, pp. 89-95.  相似文献   

7.
Efforts to monitor and map the changing water level and shoreline of a large mountain lake in Central Asia with aerial photographs are described. The essence of the work involved the mapping of the shoreline and position of river deltas from air photos from various years during the period 1949-1980, at uniform scale and at a level of accuracy permitting the quantitative (cartometric) as well as qualitative assessment of change. The sequence of work in compilation of map-diagrams for different parts of the shoreline involved the preliminary referencing of photos to a map, photo interpretation and compilation of large-scale “graphic diagrams,” preparation of a cartographic base, reduction and placement of diagrams on the base, and transformation of the image as a whole. Results of analysis of these map-diagrams are summarized. Translated from: Vestnik Leningradskogo Universiteta, ser. 7: geologiya, geografiya, 1986, No. 2, pp. 44-48.  相似文献   

8.
A Russian geographer describes a methodology whereby data on slopes contained within a geographic information system are employed in the compilation of geomorphological maps. More specifically, the author proposes and tests a technology for the automated compilation of electronic maps of mean slope for the territory of Altay Kray, West Siberia, Russia. Translated by Edward Torrey, Alexandria, Virginia from: Geografiya i prirodnyye resursy, 2002, No. 2, pp. 142-146.  相似文献   

9.
《测量评论》2013,45(7):18-21
  相似文献   

10.
《测量评论》2013,45(18):241-242
Abstract

In working out vertical heights on the Akuse-Kete Krachi chain of triangulation in the Gold Coast a fairly considerable difference was found between values of the coefficient of refraction obtained from observations taken during the day and those taken at night, the mean values being 0.069 for daylight observations to heliographs and 0.087 for night observations to lamps. This difference no doubt is due mainly to the condition of the atmosphere during the day differing from its condition during the night rather than to any effect due to different sources of light. A new chain has recently been observed in Western Ashanti, and the index of refraction for the daylight observations again gave a lower value than that obtained from the night observations, the figures being 0.073 and 0.099 respectively. For the night work three different sources of light were used, hurricane lamps for short lines, Tilley vapour-pressure lamps for lines of intermediate length, and McCaw acetylene signalling lamps by Watts for long lines. It occurred, therefore, to the writer to examine the results to see if the mean values of the index of refraction showed any variations for the different light sources, since it seemed reasonable to suppose that the constitution of the light emitted from each source would be different and hence that the coefficient of refraction might vary.  相似文献   

11.
《测量评论》2013,45(29):413-417
Abstract

In the E.S.R. No. 17 of July 1935, page 138, there appeared an article by Prof. F. A. Redmond on “The use of Even Angles in Stadia Surveying”. Since I have given this method a six-months' test in the field, using Prof. Redmond's “Tacheometric Tables” for the reduction of the measurements, the conclusions reached may be of some interest.  相似文献   

12.
EPOCH‘92全球GPS联测部分站资料的处理结果   总被引：2，自引：1，他引：2  
王解先  何妙福 《测绘学报》1994,23(3):210-215
ＩＧＳ在１９９２．６．２１～１９９２．９．２２组织了全球ＧＰＳ联测，在此期间的７．２６～８．８二周时间为加强观测，参加台站多达６００余个，用以研究ＧＰＳ的各个方面，取名为ＥＰＯＣＨ＇９２。本文对ＥＰＯＣＨ＇９２期间前后共１８天的全球分布的２４个站的资料进行了归算处理，得到的基线精度为５ｍｍ＋８．３５ｐｐｂ，定轨精度好于２ｍ，地球定向参数ｘｐ，ｙｐ解的精度约为１ｍａｓ。  相似文献   

13.
The paper describes a program for the complex (comprehensive) automated mapping of Moscow Oblast, performed jointly by various departments within the Moscow University Geography Faculty. The program was instituted during the Eleventh Five-Year Plan (1981-1985) and includes among its objectives: (1) support for local economic management and planning; (2) promotion of basic research in automated cartographic and geographic information systems; and (3) the improvement of methods of complex mapping. A number of maps compiled to date are described, and sample maps produced by the Moscow University Automated Mapping System are presented. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1988, No. 1, pp. 54-59 by Jay K. Mitchell; PlanEcon, Inc.; Washington, DC 20005.  相似文献   

14.
《测量评论》2013,45(15):2-5
Abstract

IN the July issue of the Empire Survey Review, vol. ii, no. 13, pp· 424–8, there appeared a review of precise theodolite investigations carried out by the present writers; the original papers were published in the March, 1934, number of the Canadian Journal of Research of the National Research Council, Ottawa. The elaboration of some points which could not be given much space either in the original papers or in the review may be of interest.  相似文献   

15.
The authors describe the principles and method used in compiling a map of game animal resources for the Midlands region, the name given to the middle segment of the Soviet Union comprising West Siberia, Kazakhstan and Central Asia. The results make it possible to recommend the optimal use of game resources and to identify future prospects of the trapping and hunting economy. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1982, No. 5, pp. 17-23.  相似文献   

16.
Procedures for the compilation of new maps showing the quantity and intensity of precipitation, which take into account its frequency, are outlined. The maps were prepared for the atlas The Natural Environment and Natural Resources of the World. A comparison is made with earlier published maps compiled by other methods. Translated by Jay K. Mitchell, PlanEcon, Inc., Washington, DC from: Izvestiya Akademii Nauk SSSR, seriya geograficheskaya, 1990, No. 2, pp. 5–16.  相似文献   

17.
《测量评论》2013,45(22):450-459
Abstract

Angular and Linear Errors.—In the results which follow, the number of stations quoted on the chains is exclusive of all the stations on the base-extension nets at Minna, Rijau, Chafe, and Naraguta. The total number of stations can therefore be obtained by adding the numbers on all the chains and the base-extension nets and deducting the number of points common to other chains. The quoted fractional misclosures in length are the actual misclosures obtained and the theoretical fractional misclosures which might be expected to be developed through the chains from the probable errors of the adjusted angles.  相似文献   

18.
A method for determining areas of most intensive melting within a mountain snowpack is described, based on an inverse relationship between reflectance and age of snow at wavelengths greater than 0.8 μm. Comparisons between the area of snow cover detected on visible and near infrared satellite imagery at different times during the spring thaw, and more specifically differences in position of the snowline, permit identification of the upper boundary of a zone of intensive snow-melt and water discharge from the snow cover. Translated from: Distantsionnyye Issledovaniya rel'yefa Sibiri, A. L. Yanshin and V. N. Sharapov, eds. Novosibirsk: Nauka, 1985, pp. 88-91.  相似文献   

19.
none 《测量评论》2013,45(86):363-371
Abstract

The constant K in equation (12) represents distance expended through time lags in the instrument itself, and, although the value of K can be calculated from electrical data, this would not be very satisfactory and it would be better to determine it directly by means of observations over a line of known length. In addition, the point from which K would be reckoned is not a convenient one for actual field measurements. Instead of this, it is more convenient to choose an index mark on the instrument itself and referall measurements to this and thence to the mark over which the instrument is set up.  相似文献   

20.
This study aims to illustrate how remotely sensed oceanic variables and fishing operations data can be used to predict suitable habitat of fishery resources in Geographic Information System. We used sea surface height anomaly (SSHa), sea surface temperature (SST), chlorophyll concentration (CC), photosynthetically active radiation (PAR) and fishing depth as predictor variables. Fishery data of Indian squid (Loligo spp.) and catfish (Tachysurus spp.) for study period (1998–2004) were segregated randomly to create training and validation. Catch was normalized into Catch per unit Effort (kg h?1). Generalized additive modelling was performed on training data and then tested on validation data. Suitable ranges of SST, CC, SSHa and PAR for different species distributions were derived and integrated to predict their spatial distributions. Results indicated good match between predicted and actual catch. Monthly probability maps of predicted habitat areas coincide with high catch of the particular month for the study period.  相似文献   

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