1、 Recommendation ITU-R RS.1883(02/2011)Use of remote sensing systems in the study of climate change and the effects thereofRS SeriesRemote sensing systemsii Rec. ITU-R RS.1883 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the
2、radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regiona
3、l Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submiss
4、ion of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Reco
5、mmendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur
6、 and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathe
7、ring TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2011 ITU 2011 All rights reserved. No part of this publication may be re
8、produced, by any means whatsoever, without written permission of ITU. Rec. ITU-R RS.1883 1 RECOMMENDATION ITU-R RS.1883 Use of remote sensing systems in the study of climate change and the effects thereof (2011) Scope This Recommendation provides guidelines on the provision of satellite-provided rem
9、ote sensing data for the purpose of studying climate change. The ITU Radiocommunication Assembly, considering a) that climate change is a global phenomenon affecting all humankind; b) that climate change is expected to be manifested by serious changes in the Earths environment in turn giving rise to
10、, or exacerbating, natural disasters; c) that inherent to the study of climate change are truly consistent, global Earth observing capabilities uniquely met by satellite-borne remote sensing instrumentation or sensors; d) that such satellite-borne remote sensors exist and are operated in frequency b
11、ands allocated to the Earth exploration-satellite service (EESS) today, recognizing a) that Resolution 673 (WRC-07) Radiocommunications use for Earth observation applications, considered that “Earth observation data are also essential for monitoring and predicting climate changes, . for increasing t
12、he understanding, modelling and verification of all aspects of climate change, and for related policy-making, and further noted that more than 90% of natural disasters are climate- or weather-related; . that, although meteorological and Earth observation satellites are currently only operated by a l
13、imited number of countries, the data and/or related analyses resulting from their operation are distributed and used globally . by climate-change-related organizations”; b) that Resolution 672 (WRC-07) Extension of the allocation to the meteorological-satellite service in the band 7 750-7 850 MHz, r
14、ecognized that the data obtained by these meteorological satellites are essential for global weather forecast, climate changes and hazard predictions, noting a) that ITU-T Resolution 73 Information and communications technologies and climate change, recognized that information and communications tec
15、hnologies (ICTs) can make a substantial contribution to mitigating and adapting to the effects of climate change, as presented in Annex 1, and that ICTs play a vital role in monitoring and addressing climate change by supporting basic scientific research, which has helped to bring the issue of clima
16、te change into the public domain and to raise awareness of future challenges; 2 Rec. ITU-R RS.1883 b) that ITU Report ITU and climate change, speaks to strengthening strategic partnerships with various UN agencies, the World Bank, the European Commission, international and national agencies and orga
17、nizations (for example, meteorological agencies, the Group on Earth Observations, EUMETSAT, ESA, the Space Frequency Coordination Group, JAXA, NOAA, NASA and Roscosmos), NGOs and the private sector involved in combating climate change and addressed the role that EESS plays in monitoring climate chan
18、ge; c) that Report ITU-R RS.2178 provides an extensive overview of different radiocommunication applications employed for Earth observation, space research and radio astronomy and describes their societal weight and economic benefits for the global community and, especially, their importance for cli
19、mate change monitoring and climate change prediction, and for early warning, monitoring and mitigation of man-made and natural disasters, recommends 1 that administrations should recognize the importance of satellite-borne remote sensors to the study of climate change as explained in Annexes; 2 that
20、 operators should continue supplying climate-related environmental data; 3 that the protections given to systems providing crucial climatological observations should be emphasized. Annex 1 Use of remote sensing systems in the study of climate change and the effects thereof 1 Introduction Spacecraft
21、in the EESS routinely provide worldwide coverage with the same, or functionally identical, instruments. Thus, they provide datasets that are truly consistent over the entire globe. Frequently such datasets overlap in time and allow the construction of contiguous datasets spanning decades. While such
22、 datasets do not span centuries or millennia, they nonetheless provide crucial data to those studying climate change. Satellites are the best means of providing a snapshot of the present state of our planet from a single, unified perspective. No single instrument spacecraft can provide a complete pi
23、cture; however, the current fleet of spacecraft, operating in concert and sharing their data, arguably give us the best assessment of global conditions available to us. These data serve two purposes: to provide a baseline for observing and measuring climate change and its effects upon the planet; to
24、 provide scientifically sound input to climate models. Rec. ITU-R RS.1883 3 Climate science has advanced spectacularly through satellite observations. The radiometer flown on Explorer 7 from 1959 to 1961 made possible the direct measurement of the energy entering and leaving Earth. This mission and
25、follow-on missions enabled scientists to measure Earths energy balance with much greater confidence compared to earlier indirect estimates and resulted in improved climate models. As radiometers improved, these measurements achieved the precision, spatial resolution, and global coverage necessary to
26、 observe directly the perturbations in Earths global energy budget associated with short-term events such as major volcanic eruptions or the El Nio-Southern Oscillation (ENSO). These radiometers directly measure the equator-to-pole heat transport by the climate system, the greenhouse effect of atmos
27、phere trace gases, and the effect of clouds on the energy budget of Earth. These observations have advanced our understanding of the climate system and improved climate models. Satellites engaged in atmospheric research (e.g. AURA) and supporting operational meteorology (e.g. the European MetOp seri
28、es and the National Oceanic and Atmospheric Administration (NOAA) series of polar-orbiting satellites) provide daily three-dimensional worldwide profiles of atmospheric temperature and humidity as well as data regarding minor atmospheric constituents, such as ozone. While these data are fed into wea
29、ther forecasting models, they also serve to define the current state of the atmosphere and to provide a short-term test of climate models. Other terrestrial features are monitored by spacecraft not engaged by atmosphere-related endeavours. For example, we can note: the Landsat and SPOT series of spa
30、cecraft have been monitoring the Earths surface for decades; the QuikSCAT and ADEOS-1 and -2 monitored sea surface winds; the TOPEX/Poseidon and the Jason series have been monitoring sea surface heights and temperatures; the SMOS satellite and others such as Aquarius and SMAP monitor, or will monito
31、r, soil moisture and ocean salinity. Other spacecraft and techniques, such as synthetic aperture radar (SAR) and passive microwave observations, are adding to our capabilities for describing our planet, particularly in observing the Polar Regions where winter darkness precludes taking optical images
32、. 2 Ice or the cryosphere One of the central questions in climate change and cryosphere (ice-region) research is how the warming climate will affect the ice sheets. It is important since the amount of continental ice and melt water entering the ocean strongly contributes to the change in sea level.
33、Prior to the advent of satellites, polar data was restricted to data locally gathered during hospitable seasons. The use of satellite-borne radio instrumentation has proven particularly useful in polar regions as such regions have extended periods of darkness during winter, when observations in the
34、visible spectrum are precluded. The synoptic view from satellites, particularly from satellites equipped with radio sensors, has increased polar data coverage by multiple orders of magnitude, and access is no longer restricted by seasons. Before satellites, Antarcticas and Greenlands ice sheet mass
35、balance was assumed to be controlled by the difference between ice melting and accumulation rates, and the rate of ice discharge into the ocean was assumed to be constant. Satellite radar images from RADARSAT revealed that: 1. the velocity of ice sheet flow is highly variable; 2. there exist complex
36、 networks of ice streams; 4 Rec. ITU-R RS.1883 3. the velocity of ice stream flow toward the sea has increased measurably in response to climate change. One indication of climate change/global warming is the retreat, rather than advance, of ice sheet flows (both glaciers and sea ice). The study of g
37、lacier regimes worldwide reveals widespread wastage since the late 1970s, with a marked acceleration in the late 1980s. Remote sensing is used to document changes in glacier extent (the size of the glacier) and the position of the equilibrium line (the elevation on the glacier where winter accumulat
38、ion is balanced by summer melt). Since 1972, satellites have provided optical imagery of glacier extent. SAR is now used to study zones of glacial snow accumulation and ice melt to determine climate forcing, and laser altimetry is used as well to measure change in glacier elevation. Because glaciers
39、 respond to past and current climatic changes, a complete global glacier inventory is being developed to track the current extent as well as the rates of change of the worlds glaciers. The Global Land Ice Measurements from Space project is using data from the ASTER and the Landsat Enhanced Thematic
40、Mapper to inventory about 160 000 glaciers worldwide. These measurements and the resulting trend analyses are important indicators of climate change and exemplify the value and importance of long-term data sets for understanding the complex climate system. Ice sheets can be easily monitored by space
41、-borne instrumentation, both active and passive. The breakups of major ice sheets (e.g. the Larsen Ice Shelf B) in the Antarctic have been observed from space. These breakups, if not attributed to global warming, have been accelerated by it. The collapse of the Larsen B Ice Shelf in Antarctica in 20
42、02 captured only because of frequent coverage by satellite imagery dramatically illustrated the dynamics of ice sheets on astonishingly short time-scales (Fig. 1). These revelations carry weighty implications: the rapid transfer of ice from the continental ice sheets to the sea could result in a sig
43、nificant rise of sea level. Rec. ITU-R RS.1883 5 FIGURE 1 The collapse of the Larsen B Ice Shelf in Western Antarctica. 2 000 km2, of ice shelf disintegrated in just 2 days a 31 Jan 2002 b 17 Feb 2002c 23 Feb 2002 d 05 Mar 2002Source: Earth Observations from Space: the First 50 Years of Scientific A
44、chievements, p. 3, 2008, downloadable from URL: http:/www.nap.edu/catalog/11991.html. Sea ice has been monitored continuously with passive microwave sensors (electrically scanning microwave radiometer (ESMR), scanning multichannel microwave radiometer (SMMR), special sensor microwave/imager (SSM/I),
45、 and advanced microwave scanning radiometer-Earth observing system (AMSR-E) since 1979. Not limited by weather conditions or light levels, they are well suited for monitoring sea ice because of the strong contrast in microwave emission between open and ice-covered ocean. The long-term 35-year data s
46、et from these passive microwave sensors has enabled a trend analysis extending beyond the strong interannual variability of sea ice. Since 2000, record summer ice minima have been observed during 4 out of the past 6 years in the Arctic (Figs 2 and 3). Moreover, most recent indications are that winte
47、r ice extent is now also starting to retreat at a faster rate, possibly as a result of the oceanic warming associated with a thinner, less extensive ice cover. These observations of shrinking Arctic sea ice are consistent with climate model predictions of enhanced high-latitude warming, which in tur
48、n are driven in 6 Rec. ITU-R RS.1883 significant part by ice-albedo feedback. In contrast to the Arctic, no clear trend in the extent of Antarctic sea ice coverage has been detected. FIGURE 2 Arctic sea ice extent for September 2008 was 4.67 million km2(1.80 million square miles), the second-lowest
49、in the satellite record. The magenta line shows the median ice extent for September from 1979 to 2000 September 2008Total extent = 4.7 million km2Source URL: http:/nsidc.org/news/press/20081002_seaice_pressrelease.html. Rec. ITU-R RS.1883 7 FIGURE 3 September ice extent from 1979 to 2008 shows a thirty-year decline. The September rate of sea ice decline since 1979 has now increased to 11.7% per decade YearExtent(millionkm)2NationalsnowandicedatacenterSource: URL: http:/nsidc.org/news/press/20081002_seaice_pressrelease.html. Over the past few years, ther
