EO Satellites Research Articles

Simulating arbitrary hyperspectral bandsets from multispectral observations via a generic Earth Observation-Land Data Assimilation System (EO-LDAS)

This paper presents results of using multi-sensor and multi-angular constraints in the generic Earth Observation-Land Data Assimilation System (EO-LDAS) for reproducing arbitrary bandsets of hyperspectral reflectance at the top-of-canopy (TOC) level by merging observations from multispectral sensors with different spectral characteristics. This is demonstrated by combining Multi-angle Imaging Spectroradiometer (MISR) and Landsat Enhanced Thematic Mapper Plus (ETM+) data to simulate the Compact High Resolution Imaging Spectrometer CHRIS/PROBA hyperspectral signal over an agricultural test site, in Barrax, Spain. However, the method can be more generally applied to any combination of spectral data, providing a tool for merging EO data to any arbitrary hyperspectral bandset.Comparisons are presented using both synthetic and observed MISR and Landsat data, and retrieving surface biophysical properties. We find that when using simulated MISR and Landsat data, the CHRIS/PROBA hyperspectral signal is reproduced with RMSE 0.0001–0.04. LAI is retrieved with r2 from 0.97 to 0.99 and RMSE of from 0.21 to 0.38. The results based on observed MISR and Landsat data have lower performances, with RMSE for the reproduced CHRIS/PROBA hyperspectral signal varying from 0.007 to 0.2. LAI is retrievedwith r2 from 0.7 to 0.9 and RMSE from 0.7 to 1.4. We found that for the data considered here the main spectral variations in the visible and near infrared regions can be described by a limited number of parameters (3–4) that can be estimated from multispectral information. Results show that the method can be used to simulate arbitrary bandsets, which will be of importance to any application which requires combining new and existing streams of new EO data in the optical domain, particularly intercalibration of EO satellites in order to get continuous time series of surface reflectance, across programmes and sensors of different designs.

STUDY ON PROCESS COORDINATION CAPABILITY FOR EARTH SURFACE IMAGING VIA VNREDSAT-1 OF VIETNAM AND BKA OF BELARUS

Leading companies in the field of obtaining data from Earth remote sensing from space are building Satellite constellations to increase the frequency (multiplicity) and monitor various parts of the Earth’s surface. The Satellite constellation remote sensing equipment from Airbus (France) allows daily observation of any point on the Earth’s surface with high spatial resolution, and the grouping of DigitalGlobe (USA) – with ultra-high spatial resolution. The analysis of the mutual exploitation of the national space systems of the Socialist Republic of Vietnam and the Republic of Belarus has been carried out. There have been analyzed the joint capabilities of VNREDSat-1 (Vietnam) and BKA (Belarus) Earth Observation Systems for the monitoring of natural resources, the environment and natural disasters by comparison of their space and temporal characteristics (orbit parameters and re-visit time) as well as spectral-energetic characteristics (space, spectral and radiometric resolutions). The accepted correlation of technical parameters for solving the previously mentioned tasks having into account the different phases of the mentioned satellites has been determined. The conclusions have been reinforced by the results of live experiments with archival and instant data from both EO satellites.

Privatizing Space Missions: The Critical Route to Boost Indian Space Economy

Space-based services in India have reached a stage where demand is outpacing supply and is creating a unique opportunity for developing space industry. A major outcome of advances in space, information, and communications technologies, coupled with changes in policy environment in India, immensely favors deregulation of space activities in a strategic manner into a public–private domain; thrusted private sector investments and space assets ownership and operations; space services to burgeoning domestic demand and impacting global businesses; creating high technology manufacturing capability, and competitive alliances and cooperation. Prospects for growth of commercial space activities in India are promising given that there is still high potential for growth in demands for satellite capacity and for new services such as Geographic Information System (GIS) based decision support systems, mobile multimedia, positioning and navigation applications, disaster management support, rural connectivity and national security-related applications. Demand for satellite communications is very high with large downstream services business; constant need for repetitive and high res images from space and other platforms with downstream services potential for National GIS; expanding from a regional to a global positioning system and services and applications; large-scale supply of operational LEO/GEO launch systems capability based on operational Polar Satellite Launch Vehicle (PSLV); catering to global markets of space manufacturing/applications by offering high-quality but cost-effective Indianized solutions are classic cases that can be easily privatized and migrated from present “ISRO regime” to a combinative “ISRO+private sector” capacity for future Indian space success—founding the possibility of Indian private sector space assets ownership and operations. The article creates a case and scenario for a time-bound strategy of “license-buyback” model of thrust for private-sector manufacturing, ownership and operations of Indian space assets—especially communication satellites, EO satellites, PSLV-type launch vehicle, and so on. for space services to meet Indian requirements. This approach will also bring in private sector investment in Indian space releasing financial resources for critical advanced technology development in the public regime of ISRO. The article analyses “sample cases” from an investment scenario assessment, policy dimensions, and risk environment that would be of interest for private-sector development for Indian space.

Integrating Runoff Generation and Flow Routing in Susquehanna River Basin to Characterize Key Hydrologic Processes Contributing to Maximum Annual Flood Events

The Susquehanna River basin (SRB) is the largest U.S. watershed (71,250 km2) draining to the Atlantic Coast. It encompasses portions of New York, Pennsylvania, and Maryland. Given that annual maximum flood events commonly result from either rain-on-snow or hurricanes/tropical storms, determining the potential impacts of climate change on flooding behavior is especially challenging. This paper presents a modeling system that captures these dominant flooding processes, which is well-suited for future research investigating the impacts of regional climate change. For this study, a coupled hydrologic-hydraulic model is developed and used to estimate hourly streamflow for the period from 2000 to 2008, capturing a range annual maximum discharge phenomenon (e.g., rain-on-snow, localized convective events, and hurricanes/tropical storms). The three-layer variable infiltration capacity (VIC-3L) model is used to generate surface runoff and the vertical flux of water through the root zone at a scale of 0.025° (about 2.8 km), which are used as inputs to the Hillslope River Routing (HRR) model that operates on an irregular grid with a mean length scale of 4.7 km to simulate lateral surface and subsurface transport and channel hydraulics. The coupled model is validated using USGS daily streamflow, snow water equivalent (SWE) derived from the advanced microwave scanning radiometer for EOS (AMSR-E) satellite and snow depth from in situ measurements. The coupled model (VIC-HRR) shows good performance for both seasonal baseflow patterns and large flood events (e.g., rain-on-snow and hurricane/tropical storms). Given the SRB is commonly subjected to two types of flood events, the role of snow processes is investigated. Comparing synthetic model scenarios with and without snow processes suggests that if future climate conditions reduce winter snowfall due to warmer temperatures, but maintain total precipitation levels, annual runoff will increase and mean annual peak discharge will decrease.

Прогноз тепловой реакции городской среды Санкт-Петербурга и Киева на изменение климата (по материалам съемок спутниками EOS и Landsat)

Прогноз тепловой реакции городской среды Санкт-Петербурга и Киева на изменение климата (по материалам съемок спутниками EOS и Landsat)

COMPREHENSIVE CALIBRATION AND VALIDATION SITE FOR INFORMATION REMOTE SENSING

Abstract. As a naturally part of information technology, Remote Sensing (RS) is strongly required to provide very precise and accurate information product to serve industry, academy and the public at this information economic era. To meet the needs of high quality RS product, building a fully functional and advanced calibration system, including measuring instruments, measuring approaches and target site become extremely important. Supported by MOST of China via national plan, great progress has been made to construct a comprehensive calibration and validation (Cal&Val) site, which integrates most functions of RS sensor aviation testing, EO satellite on-orbit caration and performance assessment and RS product validation at this site located in Baotou, 600km west of Beijing. The site is equipped with various artificial standard targets, including portable and permanent targets, which supports for long-term calibration and validation. A number of fine-designed ground measuring instruments and airborne standard sensors are developed for realizing high-accuracy stepwise validation, an approach in avoiding or reducing uncertainties caused from nonsynchronized measurement. As part of contribution to worldwide Cal&Val study coordinated by CEOS-WGCV, Baotou site is offering its support to Radiometric Calibration Network of Automated Instruments (RadCalNet), with an aim of providing demonstrated global standard automated radiometric calibration service in cooperation with ESA, NASA, CNES and NPL. Furthermore, several Cal&Val campaigns have been performed during the past years to calibrate and validate the spaceborne/airborne optical and SAR sensors, and the results of some typical demonstration are discussed in this study.

Innovative Web-Based Geographic Information System for Municipal Areas and Coastal Zone Security and Threat Monitoring Using EO Satellite Data

The paper presents a novel design of a web-based Safe City & Coastal Zone GIS (SCCZ-GIS). The system integrates data acquired from different remote sensing and geospatial data sources for the purpose monitoring the security of the coastal zone, its inhabitants and critical infrastructure. The system utilizes several innovative technologies and solutions and is capable of direct co-operation with different remote sensing data sources and services, including satellite ground station and ESA Service Support Environment. The system runs in operational mode, and the results of the analysis are ready in quasi real time, that is, immediately after receiving a new scene of satellite imagery. The system may be accessed by authorized users either through a web-based client or mobile device application. The paper describes the architecture of the system and presents several case studies where the software is applied to processing of earth observation satellite and spatial analysis of coastal zone infrastructure.

JAXA Earth Observation Programs Digest

This paper digests the current and the near future scenario of the Japan Aerospace Exploration Agency (JAXA) Earth Observation Program (EOP). JAXA's EOP has over thirty years history and experiences since the mid of 1980s. Medium to large scale EO satellites with various optical and radar sensors, i.e., MOS-1/1b, JERS-1, ADEOS, ADEOS-II, ALOS, GOSAT, and GCOM-W1, were developed. ALOS-2 was launched on May 24, 2014 as the successor of the ALOS for the high resolution land monitoring in all weather conditions. Aqua/AMSR-E and TRMM/PR were onboard the NASA satellites as the international joint mission instruments. Airborne SAR systems were developed for further investigations and R&D of the SAR data. Their mission objectives fully synchronize with the Group on Earth Observation (GEO) [1].

Extracting tidal variability of sea ice concentration from AMSR‐E passive microwave single‐swath data: a case study of the Ross Sea

AbstractThe periodic divergence of stress applied by ocean tidal currents to sea ice affects the time‐averaged ice concentration (Cice) and heat and freshwater fluxes at the ocean surface. We demonstrate that, at sufficiently high latitudes, tidal variability in Cice can be extracted from single‐swath data from the Advanced Microwave Scanning Radiometer–EOS (AMSR‐E) satellite passive microwave sensor, although time intervals between swaths are irregular. For the northwest Ross Sea where tidal currents are large, tidal divergence is the dominant cause of Cice variability in winter, with a range of ±0.2 about a mean of ~0.8. Daily‐averaged Cice values vary from >0.9 at neap tides to ~0.7 at spring tides. Variability at the fundamental tidal periods is about half that expected from an inverse barotropic tide model for the Ross Sea, suggesting that the measured tidal signal in Cice may be used to diagnose sea ice mechanical properties and ice/ocean coupling.

HAITI EARTHQUAKE DAMAGE ASSESSMENT: REVIEW OF THE REMOTE SENSING ROLE

Abstract. Haiti was hit by a devastating earthquake on 12 January 2010. The immediate response to the disaster was a real turning point concerning the availability, dissemination and licensing of a huge quantity of geospatial data. Timely triggering of the Earth Observation satellites, and absence of cloud cover, allowed to acquire very high-resolution optical satellite imagery (spatial resolution up to 0.5m) over the main affected areas within a few hours of the disaster, while the whole country coverage was completed in a very short time span. Furthermore in the following days aerial imagery, high resolution SAR radar imagery as well as thermal and LiDAR data were widely acquired. The paper will show how well established remote sensing techniques allowed to carry out earthquake damage assessment in a very short time, exploiting the synergic capabilities of geospatial tools and instruments such as EO satellites, Web mapping, GIS software and volunteer mapping. In a few days several map products based on the aforementioned analysis were delivered to end users: a review of the different types and purposes of this products will be provided and discussed. An assessment of the thematic accuracy of remotely sensed based products will be carried out on the basis of a review of the several available studies focused on this issue, including the main outcomes of a validation based on a comparison with in-situ data performed by the authors.

A microwave land data assimilation system: Scheme and preliminary evaluation over China

To make use of satellite microwave observations for estimating soil moisture, a dual‐pass land data assimilation system (DLDAS) is developed in this paper by incorporating a dual‐pass assimilation framework into the Community Land Model version 3 (CLM3). In the DLDAS, the model state (volumetric soil moisture content) and model parameters are jointly optimized using the gridded Advanced Microwave Scanning Radiometer–EOS (AMSR‐E) satellite brightness temperature (Tb) data through a radiative transfer model (RTM), which acts as an observation operator to provide a link between the model states and the observational variable (i.e., Tb). The DLDAS embeds a state assimilation pass and a parameter calibration pass. In the assimilation pass, the whole soil moisture profiles are assimilated from the Tb data using an ensemble‐based four‐dimensional variational assimilation method (En4DVar). Simultaneously, several key parameters in the RTM are also optimized using the ensemble Proper Orthogonal Decomposition‐based parameter calibration approach (EnPOD_P) in the parameter optimization pass to account for their high variability or uncertainty. To quantify the impacts of the Tb assimilation on CLM3‐calculated soil moisture, the original CLM3 (Sim) and the DLDAS (Ass) were run separately over China on a 0.5° grid forced with identical, observation‐based atmospheric forcing from 2004 to 2008. Soil moisture data from 226 stations over China are averaged over seven different climate divisions and compared with the soil moisture from the Sim and Ass runs. It is found that the assimilation of the AMSR‐E Tb data through the DLDAS greatly improves the soil moisture content within the top 10 cm with reduced mean biases and enhanced correlations with the station data in all divisions except for southwest China, where the current satellite sensors may have difficulties in measuring soil moisture due to the dense vegetation and complex terrain over this region. The results suggest that the AMSR‐E Tb data can be used to improve soil moisture simulations over many regions and the DLDAS is a promising new tool for estimating soil moisture content from satellite Tb data.

Remote Mapping of Thermodynamic Index of Ecosystem Health Disturbance

The study of the ecological system (ES) reaction to anthropogenous loading (AL) has been aimed at developing the remote sensing method for quantitative mapping of AL on ES. The analysis of the problem has shown that the main approach for its solution is to assess the amount of entropy induced in ES by AL. The general formalism has been dis-cussed and the thermodynamic index of ES health disturbance (TIEHD- ) has been deduced from the conservation law as a portion of solar exergy spent by ES on the parrying entropy formed in ES due to AL with respect to the total amount of exergy of solar irradiations absorbed by ES. The technique of remote mapping of TIEHD has been developed. The maps of TIEHD and the normalized differential vegetation index (NDVI)- have been compiled on the basis of NOAA and EOS satellite data. The qualitative and quantitative analysis exhibited the best sensitivity of TIEHD to AL on ES in respect to NDVI.

Gravity wave activity during stratospheric sudden warmings in the 2007–2008 Northern Hemisphere winter

We use temperature retrievals from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC)/Formosa Satellite Mission 3 (FORMOSAT‐3) and Challenging Minisatellite Payload (CHAMP) Global Positioning Satellite (GPS) radio occultation profiles and independent temperature retrievals from the EOS satellite High Resolution Dynamics Limb Sounder (HIRDLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) aboard the TIMED satellite to investigate stratospheric sudden warming (SSW) events and the accompanying gravity wave (GW) temperature amplitudes in the 2007–2008 Northern Hemisphere winter. We identify four SSW events (including a major one) occurring from late January to late February in 2008. We detect enhanced GW amplitudes in the stratosphere and subdued GW amplitudes in the lower mesosphere during the warming events. The timing of GW enhancement/suppression and warming/cooling events was generally close (within a couple days). We also find that stratospheric GW amplitudes were generally larger at the polar vortex edge and smaller in the vortex core and outside of the vortex and that stratospheric GW amplitudes were generally small over the North Pacific. Using a simplified GW dispersion relation and a GW ray‐tracing experiment, we demonstrate that the enhanced GW amplitudes in the stratosphere during SSWs could be explained largely by GW propagation considerations. The existence of GW critical levels (the level at which the background wind is the same as the GW phase speed) near the stratopause during SSWs would block propagation of GWs into the mesosphere and thus could lead to the observed subdued GW activity in the lower mesosphere. Since this is the first study to analyze the COSMIC and CHAMP GPS temperature retrievals up to 60 km in altitude, we compare the GPS analysis with those from HIRDLS and SABER measurements. We find that the temporal variability of zonal mean temperatures derived from the GPS data is reasonable up to ∼60 km in altitude, but the GPS data were less sensitive to SSWs than the HIRDLS and SABER data. GW analysis from GPS is consistent with HIRDLS up to ∼35 km in altitude, but it seems that the small‐scale variability at higher altitudes revealed in the GPS data is questionable.

A dual‐pass variational data assimilation framework for estimating soil moisture profiles from AMSR‐E microwave brightness temperature

To overcome the difficulties in determining the optimal parameters needed for a radiative transfer model (RTM), which acts as the observational operator in a land data assimilation system, we have designed a dual‐pass assimilation (DP‐En4DVar) framework to optimize the model state (volumetric soil moisture content) and model parameters simultaneously using the gridded Advanced Microwave Scanning Radiometer–EOS (AMSR‐E) satellite brightness temperature data. This algorithm embeds a dual‐pass (the state assimilation pass and the parameter optimization pass) optimization technique based on an ensemble‐based four‐dimensional variational assimilation method and a shuffled complex evolution approach (SCE‐UA). The SCE‐UA method optimizes the parameters using observational information, thereby leading to improved simulations. The RTM is used to estimate brightness temperature from surface temperature and soil moisture. This algorithm is implemented differently in two phases: the parameter calibration phase and the pure assimilation phase. Both passes are applied in each assimilation time window during the parameter calibration phase. However, only the state assimilation pass is used in the pure assimilation phase after the parameters are determined during the parameter calibration phase. Several experiments conducted using this framework coupled partially with a land surface model (the NCAR CLM3) show that volumetric soil moisture content can be significantly improved to be comparable with in situ observations by assimilating only daily satellite brightness temperature. Furthermore, the improvement in surface soil moisture also propagates to lower layers where no observations are available.

India's EO infrastructure for disaster reduction: Lessons and perspectives

India has established a ‘critical mass’ in terms of EO infrastructure for disaster management. Starting from IRS 1A in 1980s to the most recent CARTOSAT-2, India's EO series of satellites are moving away from the generic to thematic constellations. The series of RESOURCESAT, CARTOSAT, OCEANSAT and forthcoming Radar Imaging Satellite (RISAT) satellites exemplifies the thematic characters of the EO missions. These thematic constellations, characterized with multi-platform, multi-resolution and multi-parameter EO missions, are important assets for disaster reduction. In the more specific term, these constellations in conjunction with contemporary EO missions address the critical observational gaps in terms of capturing the catastrophic events, phenomena or their attributes on real/near real time basis with appropriate spatial and temporal attributes. Using conjunctively the data primarily emanating these thematic constellations and all weather radar data from aerial platform and also from RADARSAT as gap-fillers has been a part of India's EO strategy for disaster management. The infrastructure has been addressing the observational needs in disaster management. The high resolution imaging better than one-meter spatial resolution and also Digital Elevation Models (DEM) emanating from Cartosat series are providing valuable inputs to characterize geo-physical terrain vulnerability. Radar Imaging Satellite, with all weather capability missions, is being configured for disaster management. At present, the current Indian EO satellites cover the whole world every 40 h (with different resolutions and swaths), and the efforts are towards making it better than 24 h. The efforts are on to configure RESOURCESAT 3 with wider swath of 740 km with 23 m spatial resolution and also to have AWiFS type of capability at geo-platform to improve the observational frequencies for disaster monitoring. India's EO infrastructure has responded comprehensively to all the natural disasters the country has faced in the recent times. As a member of International Charter on Space and Major Disasters, India has also been instrumental in promoting the related UN initiatives viz., RESAP of UN ESCAP, SPIDER of UN OOSA, Sentinel Asia of JAXA initiative and also of GEOSS initiative. The paper intends to illustrate India's EO strategy for disaster reduction.

Application of remote and in situ information to the management of wetlands in Poland

The protection and regeneration of wetlands has been of crucial importance as a goal in ecological research and in nature conservation for some time and is more important than ever now. Knowledge about the biophysical properties of wetlands' vegetation retrieved from satellite images enables us to improve the monitoring of these unique areas, which are otherwise very often impenetrable and therefore difficult to examine, analyze and assess by means of site visits. The Biebrza Wetlands are situated in the North-East part of Poland and are one of the largest areas made up of marshes and swamps in the entire EU. This is still one of the wildest areas and one of the least destroyed, damaged or changed by human impact. However, in the recent decades there have been attempts made to intensify and overexploit the natural resources of the region and implement new agriculture practices in the area. In this period, drainage canals have been built, and a good deal of the area has been drained. The area of this precious ecosystem covers 25 494 ha. This valuable area of peat with unique vegetation species and with very special birds is one of the most valuable areas in Europe and in 1995 was added to the list of Ramsar sites. The investigation of wetlands in the Biebrza River Valley has been carried out at ground level by taking measurements of soil moisture, evapotranspiration, Leaf Area Index, wet and dry biomass and the levels of ground water and meteorological parameters. Also examined were radiative temperature, detailed vegetation mapping, and APAR. For some years the deterioration of peat lands has been noticed due to the drying out of the area and the frequent outbreak of fires. The consequence is the succession of new vegetation and the appearance of new ecosystems. The Remote Sensing Centre in the Institute of Geodesy and Cartography has undertaken the investigation by applying ERS-2.SAR and ENVISAT ASAR of IS2 and IS4 and VV, HH, HV polarization for the purpose of modeling soil moisture and humidity changes of the area under investigation. The investigation also aimed at finding the best biophysical properties of wetlands' vegetation to characterize marshland habitats and its changes. At the same time as registering the microwave data, the optical data from Landsat ETM+, SPOT VEGETATION, ERS-2.ATSR, ENVISAT MERIS, and NOAA/AVHRR have been registered and information about the biomass and heat fluxes as sensible and latent heat has also been calculated. The vegetation indices are calculated from EO satellite data taking into account jointly the features of vegetation responsible for reflection in various bands and combining this information from several spectral bands. Also, the changes in the humidity of the area have been examined by extracting the backscattering coefficients from two SAR images that were taken at a similar period of the year but with a gap of 5 years. The information about soil moisture as retention, soil moisture changes, heat fluxes and evapotranspiration are all very important for estimates of CO 2 sequestration. The ENVISAT images have been obtained for the ESA AO-ID122 project. Also the SMOS and ALOS data will be applied for the Biebrza Wetlands in the future.

A new satellite retrieval method for precipitable water vapor over land and ocean

A fundamentally new method is presented for retrieving precipitable water vapor (PWV) using observations from the Advanced Microwave Scanning Radiometer for EOS (AMSR‐E) satellite instrument. Unlike all existing passive satellite methods, the new technique is applicable both day and night, over ocean and land surfaces, and with little sensitivity to clouds. The method relies on a simple but accurate parameterization for AMSR‐E polarization‐difference signals at 18.7 and 23.8 GHz. Over land, validation is based on comparisons with the SuomiNet network of ground‐based GPS receivers. With quality control measures applied, RMS retrieval errors over land are limited to approximately six mm with a linear correlation coefficient of 0.89. Differences with the operational AMSR‐E oceanic PWV product are typically less than two mm. Products based on the new method should prove valuable in weather and climate research.

Weddell Sea iceberg drift: Five years of observations

The drift of 52 icebergs tagged with GPS buoys in the Weddell Sea since 1999 has been investigated with respect to prevalent drift tracks, sea ice/iceberg interaction, and freshwater fluxes. Buoys were deployed on small‐ to medium‐sized icebergs (edge lengths ≤ 5 km) in the southwestern and eastern Weddell Sea. The basin‐scale iceberg drift of this size class was established. In the western Weddell Sea, icebergs followed a northward course with little deviation and mean daily drift rates up to 9.5 ± 7.3 km d−1. To the west of 40°W the drift of iceberg and sea ice was coherent. In the highly consolidated perennial sea ice cover of 95% the sea ice exerted a steering influence on the icebergs and was thus responsible for the coherence of the drift tracks. The northward drift of buoys to the east of 40°W was interrupted by large deviations due to the passage of low‐pressure systems. Mean daily drift rates in this area were 11.5 ± 7.2 km d−1. A lower threshold of 86% sea ice concentration for coherent sea ice/iceberg movement was determined by examining the sea ice concentration derived from Special Sensor Microwave Imager (SSM/I) and Advanced Microwave Scanning Radiometer for EOS (AMSR‐E) satellite data. The length scale of coherent movement was estimated to be at least 200 km, about half the value found for the Arctic Ocean but twice as large as previously suggested. The freshwater fluxes estimated from three iceberg export scenarios deduced from the iceberg drift pattern were highly variable. Assuming a transit time in the Weddell Sea of 1 year, the iceberg meltwater input of 31 Gt which is about a third of the basal meltwater input from the Filchner Ronne Ice Shelf but spreads across the entire Weddell Sea. Iceberg meltwater export of 14.2 × 103 m3 s−1, if all icebergs are exported, is in the lower range of freshwater export by sea ice.

Resourcesat-1: A global multi-observation mission for resources monitoring

With an array of Indian Remote Sensing Satellites (IRS), a wide variety of national applications have been developed as an inter-agency effort over the past 20 years. Now, the capacity of the programme has been extended into the global arena and IRS is providing operational data services to the global user community. The recently launched IRS satellite, Resourcesat-1, was placed into perfect orbit by India's PSLV and is providing valuable imaging services. Resourcesat-1 is actually like 3 satellites “rolled” into one, imaging a wide field of 710 km area at ∼ 55 m resolution in multispectral bands from the AWiFS, 23 m resolution in a systematic 142 km swath from four bands of the LISS-3 and the 5.8 m multi-spectral images from the most advanced sensor—LISS-4. Yet another aspect of Resourcesat-1 is it that it marks a “watershed” in terms of a quantum jump in technological capability that India has achieved compared to past missions. The mission has many newer features—the advanced imaging sensors, the more precise attitude and orbit determination systems, the satellite positioning system onboard, the mass storage devices and many other features. This mission has led IRS into a new technological era, and when combined with the technological capability of the forthcoming Cartosat missions, India would have developed technologies that will take us into the new generation of EO satellites for the coming years. This paper provides a detailed description of the Resourcesat-1 mission. From the applications point of view, Resourcesat-1 will open up new avenues for environmental monitoring and resources management—especially for vegetation assessment and disaster management support. The monitoring capability of this mission is also extremely important for a number of applications. The mission has global imaging and servicing capabilities and could be received through the Antrix-Space Imaging network, which markets Resourcesat-1 data worldwide. This paper also describes the applications potentials and global capabilities of the mission. Resourcesat-1 will have continuity and after that a new generation system will provide enhanced and more unique imaging services. Actually, India has a 25 years strategy for EO and a perspective of the same is also described in this paper.

Planned reductions threaten EOS data studies

The Earth Observatory System Data and Information System (EOSDIS) will provide a structure for data management and derived products from EOS satellite instruments slated for launch over the next 2 decades. Within the EOSDIS framework, the EOSDIS Distributed Active Archive Centers (DAACs) are responsible for providing data, information services, and support to the global change research community. Although much of the development has been in anticipation of the future launch of the EOS instruments, each of the DAACs now has significant geophysical data holdings, which will soon be available through the prototype Version 0 Information Management System.The EOS budget is facing a 9% reduction in total budget from $8 billion to $7.25 billion through FY2000. Instruments and flight operations have been cut previously, but now EOSDIS—currently at $2.5 billion—must bear a portion of the cuts of the order of $375 million. Among possible candidates for cost savings, serious consideration is being given to closure of up to three DAACs, including those at the National Snow and Ice Data Center (NSIDC), Jet Propulsion Laboratory (JPL), and Marshall Space Flight Center (MSFC). The $30–40 million savings that this produces is considerably reduced, however, by the need to consolidate their functions elsewhere, and perhaps with more complex management, higher labor, and other costs.