scholarly journals Mapping global land surface albedo from NOAA AVHRR

1999 ◽  
Vol 104 (D6) ◽  
pp. 6215-6228 ◽  
Author(s):  
I. Csiszar ◽  
G. Gutman
Keyword(s):  
Land Surface ◽  
Surface Albedo ◽  
Noaa Avhrr ◽  
Global Land

Product dependency of Fire-driven surface albedo radiative forcing global estimates: a spatial and temporal consistency analysis

2020 ◽  
Author(s):  
Bernardo Mota ◽  
Nadine Gobron ◽  
Christian Lanconelli ◽  
Fabrizio Capucci
Keyword(s):  
Land Surface ◽  
Radiative Forcing ◽  
Surface Albedo ◽  
Temporal Trends ◽  
Model Space ◽  
Earth Observation ◽  
Temporal Consistency ◽  
Burnt Area ◽  
Albedo Change ◽  
Global Land

<p><span>This paper addresses the product consistency in a cross-ECV model space driven ECV’s to estimate the radiative forcing (RF) due to the direct effect of fire- driven surface albedo change. </span><span>Monthly radiative forcing’s are modeled </span><span>using three Earth Observation land surface albedo (MCD43C3, GlobAlbedo and Copernicus Global Land Services) and five burnt area (FireCCIv4, FireCCIv5, MCD45C5, MCD64C6 and Copernicus Global Land Services) products, and the ERA5 downward Solar radiation at the Surface</span><span>. </span><span>The ensemble consistency is analyzed spatially and seasonally by vegetation cover type using the Land Cover CCI product, and using four spatial resolutions (0.05</span><span>°</span><span>, 0.10</span><span>°</span><span>, 025</span><span>°</span><span> and 0.5</span><span>°). </span><span>Results </span><span>show that depending on the combined products and spatial resolution, estimates can differ significantly. In general, higher estimates result at coarser resolutions and variation between product combinations can differ between 26% to 46%, depending on the type of vegetation. In addition, significant temporal trends of opposing signs can be detected. </span><span>This study presents an example of cross-ECV modelling. Due to the increasing number, and coverage, of Earth Observation satellite programs, these results highlight the need to assess the </span><span>fitness for purpose </span><span>of the derived products.</span></p>

scholarly journals Cross-Comparison of Global Surface Albedo Operational Products—MODIS, GLASS, and CGLS

2021 ◽  
Vol 13 (23) ◽  
pp. 4869
Author(s):  
Congying Shao ◽  
Yanmin Shuai ◽  
Latipa Tuerhanjiang ◽  
Xuexi Ma ◽  
Weijie Hu ◽  
...  
Keyword(s):  
Energy Balance ◽  
Land Surface ◽  
Surface Albedo ◽  
Relative Difference ◽  
Surface Radiation ◽  
Radiation Budget ◽  
Dynamic Monitoring ◽  
Absolute Difference ◽  
Global Land ◽  
Global Mean

Surface albedo, as an important parameter for land surface geo-biophysical and geo-biochemical processes, has been widely used in the research communities involved in surface energy balance, weather forecasting, atmospheric circulation, and land surface process models. In recent years, operational products using satellite-based surface albedo have, from time to time, been rapidly developed, contributing significantly to the estimation of energy balance at regional or global scales. The increasing number of research topics on dynamic monitoring at a decades-long scale requires a combination of albedo products generated from various sensors or programs, while the quantitative assessment of agreement or divergence among different surface albedo products still needs further understanding. In this paper, we investigated the consistency of three classical operational surface albedo products that have been frequently used by researchers globally via the official issued datasets-MODIS, GLASS (Global LAnd Surface Satellite), and CGLS (Copernicus Global Land Service). The cross-comparison was performed on all the identical dates available during 2000–2017 to represent four season-phases. We investigated the pixel-based validity of each product, consistency of global annual mean, spatial distribution and different temporal dynamics among the discussed products in white-sky (WSA) and black-sky (BSA) albedo at visible (VIS), near-infrared (NIR), and shortwave (SW) regimes. Further, varying features along with the change of seasons was also examined. In addition, the variation in accuracy of shortwave albedo magnitude was explored using ground measurements collected by the Baseline Surface Radiation Network (BSRN) and the Surface Radiation Budget Network (SUFRAD). Results show that: (1) All three products can provide valid long-term albedo for dominant land surface, while GLASS can provide additional estimation over sea surfaces, with the highest percentage of valid land surface pixels, at up to 93% in October 24. The invalid pixels mainly existed in the 50°N–60°N latitude belt in December for GLASS, Central Africa in April and August for MODIS, and northern high latitudes for CGLS. (2) The global mean albedo of CGLS at the investigated bands has significantly higher values than those of MODIS and GLASS, with a relative difference of ~20% among the three products. The global mean albedo of MODIS and GLASS show a generally increasing trend from April to December, with an abrupt rise at NIR and SW of CGLS in June of 2014. Compared with SW and VIS bands, the linear temporal trend of the NIR global albedo mean in three products continues to increase, but the slope of CGLS is 10–100 times greater than that of the other two products. (3) The differences in albedo, which are higher in April, October, and December than in August, exhibit a small variation over the main global land surface regions, except for Central Eurasia, North Africa, and middle North America. The magnitude of global absolute difference among the three products usually varies within 0.02–0.06, but with the largest value occasionally exceeding 0.1. The relative difference is mainly within 10%–20%, and can deviate more than 40% away from the baseline. In addition, CGLS has a greater opportunity to achieve the largest difference compared with MODIS and GLASS. (4) The comparison with ground measurements indicates that MODIS generally performs better than GLASS and CGLS at the sites discussed. This study demonstrates that apparent differences exist among the three investigated albedo products due to the ingested source data, algorithm, atmosphere correction etc., and also points at caution regarding data fusion when multiple albedo products were organized to serve the following applications.

The Driving Factors of Global Land Surface Albedo: An Analysis with the Glass and Merra-2 Data

2021 ◽  
Author(s):  
Xijia Li ◽  
Ying Qu ◽  
Mingzhu Lv ◽  
Yan Song ◽  
Xinwei Zhao
Keyword(s):  
Land Surface ◽  
Surface Albedo ◽  
Driving Factors ◽  
Global Land

scholarly journals Evaluation of Two Global Land Surface Albedo Datasets Distributed by the Copernicus Climate Change Service and the EUMETSAT LSA-SAF

2020 ◽  
Vol 12 (11) ◽  
pp. 1888
Author(s):  
Gabriel Lellouch ◽  
Dominique Carrer ◽  
Chloé Vincent ◽  
Mickael Pardé ◽  
Sandra C. Frietas ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Land Surface ◽  
Surface Albedo ◽  
Global Climate ◽  
Evaluation Study ◽  
Absolute Value ◽  
Land Cover Types ◽  
Relative Value ◽  
Global Land

The present paper is devoted to the quality assessment of two global land surface albedo products developed by Meteo France in the frame of the Copernicus Climate Change Service (C3S) and the LSA-SAF (Satellite Application Facility on Land Surface Analysis), herein called, respectively, VGT (VeGeTation) (the C3Sv1 dataset, derived from VGT sensors onboard Satellites for the Observation of the Earth, also called SPOT) and ETAL (European polar system Ten-day surface ALbedo, derived from Advanced Very High Resolution Radiometers (AVHRR) onboard METeorological OPerational (METOP) satellites). The evaluation study inter-compared these products with measurements at 33 ground stations and two independent operational products, MTAL-R/NRT (Meteosat second generation Ten-day ALbedo Reprocessed/Near Real-Time) and MODIS (MODerate resolution Imaging Spectroradiometer), over two distinct four-year periods. In accordance with the prescription from the Land Product Validation group of the joint Committee on Earth Observation Satellites (LPV/CEOS), the evaluation was addressed per land cover; furthermore, two albedo regimes were considered throughout the evaluation to distinguish between high (over 0.15) and low (below 0.15) surface albedo behaviors. First, we show that both VGT and ETAL products agree well with the measurements and the other satellite products at the ground stations. Second, when inter-compared with MODIS, the results are noteworthy for ETAL as opposed to VGT, with 11 out of 13 land cover types passing the Global Climate Observing System (GCOS) requirements for more than 80% of the sites for albedo values less than 0.15 (compared with none for VGT) and 10 out of 14 land cover types passing the GCOS requirements for more than 50% of the sites for albedo values greater than 0.15 (compared with 5 for VGT). Finally, a pixel-by-pixel analysis reveals that VGT overestimates the surface albedo as compared with MODIS by about 0.02 in absolute value for albedo values less than 0.15 and by about 22% in relative value for albedo values greater than 0.15. The root-mean-square-deviation (RMSD) in absolute value is about 0.015 for albedo values less than 0.15 and 51.5% in relative value for albedo values greater than 0.15. In contrast, the bias for ETAL when compared with MODIS remains very small. Over the four-year period, ETAL overestimates the surface albedo as compared with MODIS by 0.001 in absolute value for the regime of surface albedo less than 0.15 and by about 5.8% in relative value for albedo values greater than 0.15. The RMSD in absolute value is about 0.014 for albedo values less than 0.15 and 19.4% in relative value for albedo values greater than 0.15. Assuming that the MODIS product is a good reference, a relative bias of around 6% can be judged satisfactory for ETAL surface albedo. The lower performance of the VGT (C3Sv1) product is currently the subject of investigation. Work is ongoing to upgrade it further towards the final C3S product.

Global land-surface albedo modelling

1993 ◽  
Vol 13 (5) ◽  
pp. 473-495 ◽  
Author(s):  
Clinton M. Rowe
Keyword(s):  
Land Surface ◽  
Surface Albedo ◽  
Global Land

scholarly journals OPERATIONAL 333m BIOPHYSICAL PRODUCTS OF THE COPERNICUS GLOBAL LAND SERVICE FOR AGRICULTURE MONITORING

2015 ◽  
Vol XL-7/W3 ◽  
pp. 53-56 ◽  
Author(s):  
R. Lacaze ◽  
B. Smets ◽  
F. Baret ◽  
M. Weiss ◽  
D. Ramon ◽  
...  
Keyword(s):  
Distribution System ◽  
Land Surface ◽  
Surface Albedo ◽  
Water Cycle ◽  
Vegetation Indices ◽  
Sensor Data ◽  
Current Status ◽  
Vegetation Dynamic ◽  
Area Index ◽  
Global Land

The Copernicus Global Land service provides continuously a set of bio-geophysical variables describing, over the whole globe, the vegetation dynamic, the energy budget at the continental surface and some components of the water cycle. These generic products serve numerous applications including agriculture and food security monitoring. The portfolio of the Copernicus Global Land service contains Essential Climate Variables like the Leaf Area Index (LAI), the Fraction of PAR absorbed by the vegetation (FAPAR), the surface albedo, the Land Surface Temperature, the soil moisture, the burnt areas, the areas of water bodies, and additional vegetation indices. They are generated every hour, every day or every 10 days on a reliable automatic basis from Earth Observation satellite data. Beside this timely production, the available historical archives have been processed, using the same innovative algorithms, to get consistent time series as long as possible. All products are accessible, free of charge after registration through FTP/HTTP (<a href="http://land.copernicus.eu/global/"target="_blank">http://land.copernicus.eu/global/</a>) and through the GEONETCast satellite distribution system. The evolution of the service towards the operations at 333m resolution is partly supported by the FP7/ImagineS project which focuses on the retrieval of LAI, FAPAR, fraction of vegetation cover and surface albedo from PROBA-V sensor data. The paper presents the innovations of the 333m biophysical products, make an overview of their current status, and introduce the next steps of the evolution of the Copernicus Global Land service.

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