Glacier area change (1993-2019) and its relationship to debris cover, proglacial lakes, and morphological parameters in the Chandra-Bhaga Basin, Western Himalaya, India

Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers.The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya)for the years 1993,2000,2010,and 2019 using Landsat Thematic Mapper(TM),Enhanced Thematic Mapper(ETM),and Operational Land Imager(OLI)datasets.A total of 251 glaciers,each having an area above 0.5 km^(2),were identified,which include 216 clean-ice and 35 debris-covered glaciers.Area changes are estimated for three periods:1993-2000,2000-2010,and 2010-2019.The total glacierized area was 996±62 km^(2) in 1993,which decreased to 973±70 km^(2) in 2019.The mean rate of glacier area loss was higher in the recent decade(2010-2019),at 0.036 km^(2),compared to previous decades(0.029 km^(2) in 2000-2010 and 0.025 km^(2) in 1993-2000).Supraglacial debris cover changes are also mapped over the period of 1993 and 2019.It is found that the supraglacial debris cover increased by 14.12±2.54 km^(2)(15.2%)during 1993-2019.Extensive field surveys on Chhota Shigri,Panchi II,Patsio,Hamtah,Mulkila,and Yoche Lungpa glaciers were carried out to validate the glacier outlines and supraglacial debris cover estimated using satellite datasets.Controls of various morphological parameters on retreat were also analyzed.It is observed that small,clean ice,south oriented glaciers,and glaciers with proglacial lakes are losing area at faster rates than other glaciers in the basin.

Significance of glacio-morphological factors in glacier retreat：a case study of part of Chenab basin,Himalaya

A study has been carried out in part of Chenab basin,Himalaya to understand the relationship between glacio-morphological factors and change in glacial area. Initially change in areal extent of glaciers was derived for two time frames(1962-2001/02 and 2001/02-2010/11). The study comprised of 324 glaciers for the monitoring period of 1962-2001/02 for,which 11% loss in glacial area was observed. Two hundred and thirty-eight glaciers were further monitored between 2001/02 and 2010/11. These glaciers showed an area loss of 1.1%. The annual deglaciation has been found to be higher during the period of 1962-2001/02 compared to 2001/02-2010/11. The spatial and temporal variability in deglaciation was also addressed usingglacio-morphic parameters. Area,length,percentage of debris cover,and various elevation parameters of glaciers were observed to have significant controls on relationships to the rate of glacial shrinkage. Largerarea and longer glaciers show a lower percentage of retreat than smaller and shorter ones. Moreover,glaciers located at lower altitudes and having gentle slopes show more area retreat. The results of area retreat in debris covered and debris free glaciers supports that the glaciers covered by debris retard ice melting at some extent. 158 glaciers were observed having no debris cover,and these exhibit 14% of loss in surface area. In glaciers having 40% debris cover,8% of deglaciation was observed. The glaciers located below equilibrium line altitude(ELA) have experienced 4.6% of deglaciation for the time frame 2001/02 – 2010/11 whereas it was found to be 1.1% for the glaciers occurring above ELA. However,theorientation of glaciers did not show any considerable influence on glacial change based on hypothesis.

Frameworks of Non-Orthogonal Multiple Access Techniques in Cognitive Radio Communication Systems

Recently,the increasing demand of radio spectrum for the next generation communication systems due to the explosive growth of applications appetite for bandwidths has led to the problem of spectrum scarcity.The potential approaches among the proposed solutions to resolve this issue are well explored cognitive radio(CR)technology and recently introduced non-orthogonal multiple access(NOMA)techniques.Both the techniques are employed for efficient spectrum utilization and assure the significant improvement in the spectral efficiency.Further,the significant improvement in spectral efficiency can be achieved by combining both the techniques.Since the CR is well-explored technique as compared to that of the NOMA in the field of communication,therefore it is worth and wise to implement this technique over the CR.In this article,we have presented the frameworks of NOMA implementation over CR as well as the feasibility of proposed frameworks.Further,the differences between proposed CR-NOMA and conventional CR frameworks are discussed.Finally,the potential issues regarding the implementation of CR-NOMA are explored.

利用卫星遥感和GIS技术测定印度切蒂斯格尔地区干旱热带森林的土地利用、生物量和碳贮量(英文)

2001-2002年间,利用卫星遥感和GIS技术研究印度切蒂斯格尔邦的赖布尔地区干旱热带森林的土地利用、生物量和碳贮量情况。主要森林类型为:柚木森林、混合林、衰退森林和婆罗双树混交林。在这些不同森林类型中,立地的坡度和坡面影响森林植被类型、生物量和碳贮量。不同森林类型中,木材积蓄积量、生物量和碳贮量的变化范围分别为:35.59～64.31 m3·hm-2、45.94～78.31Mg·hm-2和22.97～33.27Mg·hm-2。混合林中每公顷的木材蓄积量、生物量和碳贮量最大,衰退森林中的最低。混合林、柚木森林、衰退森林和婆罗双树混交林的总碳量分别为8170.72 Mg、81656.91 Mg、7833.23 Mg和7470.45 Mg。蒂斯格尔邦地区干旱热带森林处于不成熟的生长阶段,且具有很强的碳回收潜力。图6表7参49。

Inter-annual and seasonal variations in hydrological parameters and its implications on chlorophyll a distribution along the southwest coast of Bay of Bengal

Seasonal and inter-annual variability of hydrological parameters and its impact on chlorophyll distribution was studied from January 2009 to December 2011 at four coastal stations along the southwest Bay of Bengal. Statistical analysis （principal component analysis （PCA）, two-way analysis of variance （ANOVA） and correlation analysis） showed the significant impact of hydrological parameters on chlorophyll distribution in the study area. The ranges of different parameters recorded were 23.8-33.8℃ （SST）, 4.00-36.00 （salinity）, 7.0-9.2 （pH）, 4.41-8.32 mg/L （dissolved oxygen）, 0.04-2.45 μmol/L （nitrite）, 0.33-16.10 μmol/L （nitrate）, 0.02-2.51 μmol/L （ammonia）, 0.04-3.32 μmol/L （inorganic phosphate）, 10.09-85.28 μmol/L （reactive silicate） and 0.04-13.8 μg/L （chlorophyll）. PCA analysis carried out for different seasons found variations in the relationship between physico-chemical parameters and chlorophyll in which nitrate and chlorophyll were positively loaded at PC1 （principal component 1） during spring inter-monsoon and at PC2 （principal component 2） during other seasons. Likewise correlation analysis also showed significant positive relationship between chlorophyll and nutrients especially with nitrate （~0.734）. Distribution of hydrobiological parameters between stations and distances was significantly varying as evidenced from the ANOVA results. The study found that the spatial and temporal distribution of chlorophyll was highly dependent on the availability of nutrients especially, nitrate in the southwest Bay of Bengal coastal waters.

Manifestation of earthquake preparation zone in the ionosphere before 2021 Sonitpur,Assam earthquake revealed by GPS-TEC data

Global Positioning System(GPS)Continuously Operating Reference Station(CORS)data analysis shows that the ionosphere’s electron density variability is linked to the deformation and stress accumulation in the Earth’s crust.Anomalies in ionosphere total electron content(TEC)variability before 2021 M6.4 Sonitpur,Assam earthquake were detected using L1 and L2 GPS frequencies that showed three distinct abnormalities on April 3,9,10,2021.Pearson’s correlation coefficient(r)of TEC decreases in the CORS that lies away from the earthquake epicenter,indicating the possibilities of a positive relationship between TEC variability and earthquake epicenter.TEC concentration also decreases towards the epicenter within the earthquake preparation zone(EPZ).It is also observed that the Pearson’s correlation coefficient(r)of TEC decreases linearly near the EPZ.The study demonstrates the possibilities of determining the TEC anomalous zone in the ionosphere that coincides with the EPZ in the crustal rocks.The research indicated the possibilities of magnitude estimation of an impending earthquake based on the TEC anomalous zone in the ionosphere using closely spaced dense CORS network data.

Observed Relationship between Surface Freshwater Flux and Salinity in The North Indian Ocean

Using 10-year (2001 10) monthly evaporation, precipitation, and sea surface salinity (SSS) datasets, the relationship between local freshwater flux and SSS in the north Indian Ocean (NIO) is evaluated quantitatively. The results suggest a highly positive linear correlation between freshwater flux and SSS in the Arabian Sea (correlation coefficient, R=0.74) and the western equatorial Indian Ocean (R=0.73), whereas the linear relationships are relatively weaker in the Bay of Bengal (R=0.50) and the eastern equatorial Indian Ocean (R=0.40). Additionally, the interannual variations of freshwater flux and SSS and their mutual relationship are investigated in four sub- regions for pre-monsoon, monsoon, and post-monsoon seasons separately. The satellite retrievals of SSS from the Soil Moisture and Ocean Salinity (SMOS) and Aquarius missions can provide continuous and consistent SSS fields for a better understanding of its variability and the differences between the freshwater flux and SSS signals, which are commonly thought to be linearly related.

Quality assessment of Continuous Operating Reference Stations(CORS)-GPS stations in Mexico

The present analysis provided the quality assessment of 65 Continuous Operating Reference Stations(CORS) situated in and around Mexico using the data of about ten years(January 2010 to January 2020).To accomplish the assessment,we considered 4 quality indexes for performing the quality check,incluing the multipath effect on L1 and L2 bands,signal-to-noise ratio in both bands,cycle slips,and integrity.Meanwhile,a new reference parameter named regio nal values for Mexico(RVM) was calculated for the stations situated in Mexico.Additionally,an exhaustive analysis of the quality indicators in the worst and best cases was performed.The signal degradation was proved by a long-term time series and cru stal defo rmation analysis in GAMIT/GLOBK platform.The results showed a stro ng correlation between integrity,cycle slips and daily observations time,and the multipath effect is strong in the case of outdated systems.The study indicates that the estimated quality indexes and values could be the basis for establishing new CORS in Mexico,and the errors corrections which cannot be mitigated in the postprocessing stage would greatly help utilize the data for different scientific applications.The results were supported by deformation analysis in part of Baja California Peninsula in Mexico indicating northern and eastern velocity vector of -3.08±0.02 mm/yr,-7.85±0.02 mm/yr and-0.07±0.03 mm/yr,-9.33±0.02 mm/yr respectively at MPR1 and INEG stations.

The Complex Phenomenon of Glaciers of Nubra Valley, Karakorum (Ladakh), India

The Nubra valley nestled in the Karakorum Mountains of Ladakh houses about 600 glaciers of various dimensions out of which 114 glaciers were monitored in the first phase of study. The study of 114 glaciers suggests that small-sized glaciers outnumber the large-sized glaciers. Almost 52.6% of the studied glaciers are of the size less than 5 km and 31.5% of the total glaciers are between the size of 5 and 10 km. The 84 glaciers out of the 114 glaciers have been monitored on shortterm basis between the time period 1989 and 2001 whereas 30 glaciers have been monitored on long-term basis between 1969 and 2001. The monitoring of the glaciers is based on the study of Survey of India topographical sheets of 1969 and satellite imageries of time series between 1989 and 2001. The monitoring of thirty glaciers shows that 17 glaciers have lost their area between 1969 and 2001. The loss in area is from 2150 km2 in 1969 to 2026 km2 in 2001. The study of eighty- four glaciers on short-term basis between 1989 and 2001 suggests that 26 glaciers have retreated, 25 glaciers have advanced and 33 glaciers show no change during the time period. The changes in the glaciers of Nubra valley are varied and complex.

Lightning Nowcasting with an Algorithm of Thunderstorm Tracking Based on Lightning Location Data over the Beijing Area

A thunderstorm tracking algorithm is proposed to nowcast the possibility of lightning activity over an area of concern by using the total lightning data and neighborhood technique.The lightning radiation sources observed from the Beijing Lightning Network(BLNET)were used to obtain information about the thunderstorm cells,which are significantly valuable in real-time.The boundaries of thunderstorm cells were obtained through the neighborhood technique.After smoothing,these boundaries were used to track the movement of thunderstorms and then extrapolated to nowcast the lightning approaching in an area of concern.The algorithm can deliver creditable results prior to a thunderstorm arriving at the area of concern,with accuracies of 63%,80%,and 91%for lead times of 30,15,and 5 minutes,respectively.The real-time observations of total lightning appear to be significant for thunderstorm tracking and lightning nowcasting,as total lightning tracking could help to fill the observational gaps in radar reflectivity due to the attenuation by hills or other obstacles.The lightning data used in the algorithm performs well in tracking the active thunderstorm cells associated with lightning activities.

Performance analysis of cognitive radio networks using channel-prediction-probabilities and improved frame structure

This paper focuses on potential issues related to the random selection of a sensing channel that occurs after the prediction phase in a Cognitive Radio Network (CRN).A novel approach (Approach-l)for improved selection is proposed,which relies on the probabilities of channels by which they are predicted idle.Further,closed-form expressions are derived for the throughput of Cognitive Users (CUs)in the conventional and proposed approaches. In addition to this,a fimdamental approach for computing the prediction probabilities is also proposed.Moreover, a new challenging issue named "sense and stuck"was observed in the conventional approach.The proposed approach is validated by comparing the results achieved with the results of the conventional approach.However, to achieve the prediction probabilities,the pre-channel-state-information is a prerequisite,but it may be unavailable for particular scenarios;therefore,a modified selection method is introduced to avoid the sense and stuck problem.An algorithm to evaluate the throughput using the random,improved,and modified selection methods is presented with its space and time complexities.Furthermore,for additional improvement in the throughput of the CU,a new frame structure is introduced,in which the spectrum prediction and sensing periods are exploited for simultaneous transmission of data via the underlay spectrtun access technique (Approach-2).The simulated results of Approach-2 are compared with our pre-obtalned results of Approach-I,which confirm significant improvement in the throughput.

Spatial Variability and Radiative Impact of Aerosol along the Brahmaputra River Valley in India: Results from a Campaign

The first ever land campaign to study the spatial variability of the aerosol characteristics along the Brahmaputra river valley (BRV) in Assam, North-Eastern India, was conducted during 2011. Measurements were made over 13 locations for Aerosol Optical Depth (AOD), scattering coefficient, particulate matter, black carbon (BC) concentration and meteorological parameters. The BRV is divided into three sectors longitudinally viz western sector (WS), central sector (CS), and eastern sector (ES). Significant Spatial heterogeneity in AOD and BC concentration was observed (p < 0.05) with the highest values over WS and a continual decrease from WS to ES with aerosol dominance in PM2.5 category along the entire valley. The Angstrom coefficient measured using different wavelength pairs showed spatial variability indicating dominance of fine particles over WS and coarse particles in ES with a probable bimodal distribution. The scattering and absorption coefficient shows dominance of both types of aerosol over WS than other areas. The shortwave radiative forcing was higher over the WS than CS and ES of the valley. The campaign revealed that under favorable wind conditions, the BRV is loaded with significant amount of natural and anthropogenic aerosol during local winter and is influenced by the long-range transport of aerosols from the Indo-Gangetic plain.

A Geospatial Approach to Climatic Zone Specific Effective Horticultural Planning in East Khasi Hills District of Meghalaya, India

Climatic zone is one of the most important units for horticultural planning. Survival and failure of particular land use or farming system in a given region heavily relies on careful assessment of agroclimatic resources. Large variety of crops is being grown in Meghalaya traditionally, based on the needs and cultural practices of people without any consideration to the suitability of the climate. This study attempts to make adjustments with the climate based upon scientific knowledge to make the best use of the natural resources so as to recommend more area under horticultural crops. This has been made by identifying existing land use and appropriate land use strategies mainly for horticultural crops for each agro-climatic region. Modern Geospatial technology such as satellite Remote Sensing (RS) and Geographical Information System (GIS) and GPS have been used effectively to provide newer dimensions in identifying suitable sites for various horticultural crops and also for appropriate monitoring and management of land resources in an integrated manner with reference to agro-climatic condition.

Characterization and Evaluation of Natural Resources for Land Use Diversification Planning: A Case Study in a Block of Meghalaya Using RS &GIS Technique

Characterization and evaluation of land resources of Mawryngkneng block was carried out using IRS-P6 LISS III and LISS-IV data. Five major physiographic units namely structural hills, denudational hills, plateau and intermontane valley were identified. Visual interpretation of satellite data indicated that 32.2% of the total geographical area (TGA) is under dense forest followed by wastelands (28.8%), open forest (16.1%), cultivated area (13.6%), built up area (8.2%) and water body (0.9%). Ten soil series were tentatively identified and the soils belonged to 2 orders (Ultisols and Alfisols), 3 sub orders (Udult, Udalf and Humult), 6 great groups, 8 sub groups. The soils are moderately acidic, deep to very deep and texture varies from sandy clay loam to clay. The soils are very rich in organic carbon. The availability of nitrogen is medium to high and phosphorus availability is low to medium whereas potassium availability is low in the entire study area. The soils were grouped into land capability class II & III and the soils were moderately to marginally suitable for orange and marginally suitable for pine apple. An action plan with suggested land use and interventions has been prepared by using all land resource information generated under the study. The action plan includes areas for afforestation, intensive cultivation in the existing cropped areas with soil conservation measures like mulching, zero tillage etc. and orange and pine apple plantation in open scrub lands which are cultivable wastelands. This might help the farmers and the planner in better management of land resources for sustained productivity.

Development of a Web Based GIS Application for Spatial Natural Resources Information System Using Effective Open Source Software and Standards

There is growing needs for web based GIS for easy and fast dissemination, sharing, displaying and processing of spatial information which in turns helping in decision making for various natural resources based applications. In order to make a cost effective implementation, operation and maintenance of spatial information over the web, a cheaper yet feature rich alternative to commercial software is required which can be fulfilled by Open Source GIS software. This paper conveys an efficient approach to customize and integrate an open source web GIS system based on Mapserver as a web GIS server and PostgreSQL/PostGIS as an object oriented relational database management system (ORDBMS) for effective dissemination, sharing and management of spatial information over the internet. An open source web application tool built on top of MapScript using the PHP programming language has been used as for development of interactive user interface. The configurable Web Mapping Client Components (CWC2) tags have been added to HTML template pages in order to deploy the mapping contents to a web application. It is observed that the present system developed using open source software enables user to view, update, customized retrieval, query and analysis of natural resources information for specific needs.

Glacier Area Change over Past 50 Years to Stable Phase in Drass Valley, Ladakh Himalaya (India)

Glaciers are dynamic reservoirs of constantly exchanging mass with parts of global hydrological system, process by which glaciers gain or lose snow and ice and establish a link between climate, glacier mass and glacier fluvial dynamics related directly to the behaviour of climate. Here, we report on glacier status over the past 50 years (1962-2013) on remotely-sensed volumetric changes of glaciers in Drass glacier basin, Ladakh Mountain, North-West Himalaya. Drass basin houses 150 glaciers of different dimensions predominantly (nearly 75%) by small sized glaciers. The glaciers monitored on multi-temporal satellite images of the year’s 2001, 2013 for short-term basis, and, Survey of India topographic sheets of 1965 (surveyed in 1963) on long-term basis. Machoi glacier has been selected for detailed study to assess health and fluctuation record on which observation has been made since the year 1875. The long-term monitoring (1965-2001) of 81 glaciers shows that 12.5% of glaciers have gained the area whereas 14% of large glaciers lost area 5% to 15%, and remaining 73% glaciers lost area marginally (<5%). The short-term monitoring shows that 80% glaciers do not show any change in area;even large glaciers vacated 0.64% - 2.6% area and small glaciers 1.68% - 9% glacier area. The trends in annual, seasonal and monthly maximum/minimum temperature and precipitation (snowfall and rainfall) of Drass for period 1987-2013 show that two different patterns of weather conditions: 1988-2001, cold moist winters with dry summers, and 2002-2013, a period of long winters and cool and moist summers, corroborate with transitional phase of glacier behaviour. This phenomenon has resulted in incorporating no change in area of 80% of glacier (120 glaciers) and remaining 20 percentage of glaciers show marginal loss in area. The positive balance mass for last four years (2011-2014) in benchmark Machoi glacier with cumulative specific balance +0.16 m w.e/km2/yr further indicates about the stability phase of the glaciers.

Assessment of alpine summit flora in Kashmir Himalaya and its implications for long-term monitoring of climate change impacts

In an era of climate change,the availability of empirical data on alpine summit vegetation in the Himalaya is still scarce.Here we report the assessment of alpine summit flora in Gulmarg Wildlife Sanctuary,Kashmir Himalaya.We employed a globally standardized Multi-Summit Approach and four spatially isolated summits spanning an elevation gradient of 210 m(between 3530-3740 m a.s.l.)from natural treeline to nival zone were studied.Sampling of the summits was carried out in the year 2018 to collect floristic data together with records of soil temperature.A total of 142 vascular plant species were recorded in the sampled summits.Majority of the species were of herbaceous growth form and with perennial life span.Based on Raunkiaer’s life form,hemicryptophytes were the most dominant followed by therophytes and phanerophytes.The summit flora showed the predominance of narrow-endemic species,with broad-and non-endemics declining with elevation.A significant relationship between growth form,Raunkiaer’s life form,and the degree of endemism with elevation was observed.Both species diversity and soil temperature showed a monotonic decrease with increasing elevation.Interestingly,soil temperature clearly determined the magnitude of species diversity on the summits.Furthermore,based on floristic composition,the lowest summit had the highest dissimilarity with the rest of the summits.The present study employed globally standardized protocol to scientifically assess the patterns of plant diversity on the alpine mountain summits of Kashmir Himalaya,which in turn has wide implications towards long-term monitoring of climate change impact on alpine biodiversity in the rapidly warming Himalaya.

Vascular plants distribution in relation to topography and environmental variables in alpine zone of Kedarnath Wild Life Sanctuary,West Himalaya

The present study was carried out in Tungnath alpine meadows of Kedarnath Wild Life Sanctuary, Western Himalaya from subalpine to upper alpine zone. A total of four summits were selected along an altitudinal gradient and sampled for detailed vegetation analysis using multi summit approach as per Global observation research initiative in alpine environments(GLORIA). Species richness, diversity, and evenness among four summits as well as the interaction between environmental variables with plant communities were assessed. Monthly mean soil temperature was calculated using data retrieved from geo-precision temperature logger in order to identify the trend of soil temperature among different season and altitudinal gradient and its implications to plant communities. Soil samples were analyzed fromeach summit by collecting randomized composite soil samples. The indirect non-metric multidimensional scaling(NMDS) and direct canonical correspondence analysis(CCA) tools of ordination techniques to determine the linkage between plant species from various sample summits and biotic/abiotic environmental gradients were used in the present study. The results of the study demonstrated increase in species richness as soil temperature increases, the ecotone representing summits were found most warm summits followed by highest species richness. Annual soil temperature increased by 1.43°C at timberline ecotone. Whereas, at upper alpine zone the soil temperature increased by 0.810 C from year 2015 to 2016. S?rensen's similarity index was found to be increased between subalpine and upper alpine zone with increase in the presence of subalpine plant species at upper alpine zone. Both the ordination tools separate the subalpine summit and their respective vegetation from summits representingtimberline ecotone and upper alpine zone. Soil p H, altitude, soil cation exchange capacity were found as the key abiotic drivers for distribution of plant species.

Asymptotic Magnitude Bode Plots of Fractional-Order Transfer Functions

Development of asymptotic magnitude Bode plots for integer-order transfer functions is a well-established topic in the control theory.However,construction of such plots for the fractional-order transfer functions has not received much attention in the existing literature.In the present paper,we investigate in this direction and derive the procedures for sketching asymptotic magnitude Bode plots for some of the popular fractional-order controllers such as PI^α,[PI]^α,PD^β,[PD]^β,and PI^αD^β.In addition,we deduce these plots for general fractional commensurate-order transfer functions as well.As applications of this work,we illustrate 1)the analysis of the designed fractional-control loop and 2)the identification of fractional-order transfer function from a given plot.

Multi-polarized Radarsat-2 satellite sensor in assessing forest vigor from above ground biomass

Accurate estimates of forest biomass are increasingly important in relation to sequestration of carbon by forest trees. Satellite remote sensing is a useful tool for biomass estimation and monitoring of forest ecological processes. Microwave synthetic aperture radar （SAR） can increase the accuracy of estimations of forest biomass in comparison to optical remote sensing, due to the unique capacities of SAR, including high penetrability, volumetric scattering, interaction with surface roughness, and dielectric property. We studied the potential of multi-polarized C-band Radarsat-2, a SAR technology, with HH, HV and VV polarization for estimating biomass of moist tropical Indian forest. Backscatter values are correlated with fieldbased biomass values and axe regressed to generate models for estimating biomass. HH polarization provided maximum information regarding tree biomass. A coefficient of determination of 0.49 was calculated for HH polarized C-band image with in situ measurements. An exponential model was proved to be best suited for estimating forest biomass. Correlation of 0.62 and RMSE of 24.6 t ha-1 were calculated for the relationship between estimated and predicted biomass values for the best fit model. The aver- age absolute accuracy of the model was 61%, while Willmott＇s index of agreement was 0.87. Results suggest that most of the biomass of the area ranged within 70 t ha-1 a probably due to the saturation of C-band around 60-70 t ha-1 for tropical forests.