Global LAnd Surface Satellite (GLASS) Products: Characteristics and Preliminary Applications. Shunlin Liang & GLASS data production team

Transcription

1 Global LAnd Surface Satellite (GLASS) Products: Characteristics and Preliminary Applications Shunlin Liang & GLASS data production team University of Maryland and Beijing Normal University GV2M, Avignon, Feb. 6, 2014

2 Acknowledgements More than 100+ people contributing to the project for generating the GLASS products; Funding supports mainly from the 863 program of China, managed by the National Remote Sensing Center of China (NRSCC), Ministry of Science and Technology

3 Outline Overview of the GLASS products (1) Shortwave broadband albedo (2) Leaf Area Index (LAI) (3) Longwave broadband emissivity (4) Shortwave radiation (5) Photosynthetically Active Radiation (PAR) Summary

4 Global LAnd Surface Satellite (GLASS) Products Products Temporal Spatial Temporal range resolution resolution Leaf area index (LAI) km, 5km 8 days Longwave emissivity km, 5km 8 days Shortwave albedo km, 5km 8 days Incident shortwave radiation km 3 hours Incident PAR km 3 hours FREE GLASS Product Distribution Beijing Normal University (BNU) Center for Global Change data Processing and Analysis University of Maryland (UMD) Global Land Cover Facility

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6 (1) Shortwave albedo product MODIS, MISR POLDER MERIS GEOLAND2 GLOBALBEDO GLASS

7 Qu, Y., Liu, Q., Liang, S., Wang, L., Liu, N., & Liu, S. (2014). Improved direct estimation algorithm for mapping daily landsurface broadband albedo from MODIS data. IEEE Transaction on Geoscience and Remote Sensing, 52(2): Liu, N., Liu, Q., Wang, L., Liang, S., Wen, J., Qu, Y., & Liu, S. (2013a). Mapping spatially temporally continuous shortwave albedo for global land surface from MODIS data. Hydrology and Earth System Sciences, 17, Liu, Q., Wang, L., Qu, Y., Liu, N., Liu, S., Tang, H., & Liang, S. (2013b). A Preliminary Evaluation of GLASS Albedo Product. International Journal of Digital Earth, 6, MODIS data AB1 Intermediate product 2000 present AB2 Intermediate product STF Final product MCD43 albedo product Statistics data base AVHRR data AB1 Intermediate product STF Final product AB1 AB2 : Angular Bin (AB) two inversion algorithms STF Statistics-based Temporal Filtering (STF) post-processing algorithm First satellite land product based on the integration of multiple algorithms

8 Long term changes in land albedo Mean albedo Global albedo anomaly

9 Example 1: Calibrating/Validating the State of the art GCM Simulations Shortwave albedo 0.45 BCC CSM1 CanCM4 CCSM4 CFSv2 CNRM CM5 FGOALS s2 0.4 GEOS 5 GFDL CM2p1 HadCM3 IPSL CM5A LR MIROC4h MIROC5 MPI ESM LR MPI ESM MR MRI CGCM GEWEX CERES GLASS MODIS ISCCP MERIS Month Inter-comparison of 30-year global albedo climatology derived from satellite products and CMIP5 model outputs. He, et al. 2014

10 Example 2

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13 (2) Leaf area index (LAI) product LAI Products Spatial resolution Temporal resolution (day) Temporal range MODIS 1km present CYCLOPES 1/ GLOBECARBON 1/ Geoland2 1km, 0.05º GLASS 1km,

14 General Regression Neural Networks Input layer Pattern layer Summation layer Output layer MODIS reflectance data from an entire year x 1 x 2 x j x n G R N N y 1 y k y m One-year LAI profiles A GRNN with a multi-input multi-output architecture Xiao, Z., Liang, S., Wang, J., Chen, P., & Yin, X. (2014). Use of General Regression Neural Networks for Generating the GLASS Leaf Area Index Product from Time Series MODIS Surface Reflectance. IEEE Transactions on Geoscience and Remote Sensing, 52(1):

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16 (3). GLASS emissivity product Emissivity is one of the important components in land surface energy balance and has significant impacts on model simulations; R R s R l (1 ) F s F l T n n n d d albedo Insolation Emissivity Longwave downward radiation Skin temperature No global broadband emissivity satellite product yet; Most GCMs assume constant emissivity values Land surface spectral emissivity products have large errors 4

17 Jan Broadband emissivity from MODIS Aug Jin, M., and S. Liang, (2006), Impacts of the MODIS broadband emissivity on GCM simulation, J. Climate, 19:

18 Figure 14: Emissivity impacts on surface air temperature differences in the coupled CAM2/CLM2 model: default emissivity values and MODIS emissivity maps

19 products resolutions, temporal range CERES emissivity map Global, 10 10, no temporal variation MODIS based baseline fit database AIRS IASI Global, 0.05º, monthly, ºN 30ºS, monthly, April 2003 March ºN 30ºS, monthly, April 2007 March 2011 ASTER Global discontinuous, 90m, 2000 present MODIS Global coverage, 0.05º, 2000 present wavelengths 12 spectral bands and one broadband(5 100 µm) 10 wavelengths ( µm) µm ( 0.05 µm spectral resolution) µm ( 0.05 µm spectral resolution) 5bands 6bands( µm) GLASS Global, 1km, 0.05º 1 broadband (8 13.5µm)

20 GLASS Longwave Emissivity product Unique features: Took advantage of MODIS shortwave reflectance and ASTER spectral emissivity First broadband emissivity product from AVHRR data Cheng, J., S. Liang, Y. Yao, X. zhang (2013). "Estimating the Optimal Broadband Emissivity Spectral Range for Calculating Surface Longwave Net Radiation." IEEE Geoscience and Remote Sensing Letters10(2): Ren, H., S. Liang, G. Yan, J. Cheng (2013). "Empirical algorithms to map global broadband emissivities over vegetated surfaces." IEEE Transactions on Geoscience and Remote Sensing: 51(5): Cheng, J. and S. Liang (2013). "Estimating global land surface broadband thermal infrared emissivity from the Advanced Very High Resolution Radiometer optical data." International Journal of Digital Earth: 6,34 49 Cheng, J., & S. Liang, (2014). Effects of thermal infrared emissivity directionality on surface broadband emissivity and longwave net radiation estimation. IEEE Geoscience and Remote Sensing Letters, 11(2): Cheng, J., S. Liang, Y. Yao, B. Ren, L. Shi, H. Liu, (2014), A comparative study of three land surface broadband emissivity datasets from satellite data, Remote Sensing, 4(1):

21 GLASS Longwave emissivity product

22 Product intercomparison and validation Comparison with JPL/ASTER in the summer,(a)glass; (b)aster; (c) differences; (d) Histogram of the differences. Comparison with JPL/ASTER in the winter,(a) GLASS; (b)aster; (c) differences; (d) Histogram of the differences. In situ validation

23 (4) (5) shortwave radiation and PAR products current global incident shortwave radiation satellite products Insolation Products Spatial resolution Uncertainty Goal (Wm 2 ) Uncertainty threshold (Wm 2 ) Temporal resolutio n Horizontal resolution goal (km) Temporal range ISCCP 280km 3 hour GEWEX 1 3 hour SRB CERES 140km 3 hour 1997 present GLASS 5km 3 hour WMO requirements for surface downward shortwave irradiance Horizontal resolution Theshold (km) Global NWP Agricultural N/A N/A 1 20 Meteorology Climate AOPC

24 Polar Orbiting: MODIS Geostationary: GOES-W GOES-E MSG MTSAT FY2C Solar radiation on Nov. 11, 2008 PAR in July 2008

25 Validation along with other products CERES MODIS CALIPSO Site GLASS Insolation ISCCP-FD Model B CloudSat (CCCM) Enhanced R2 Bias RMSE R2 Bias RMSE R2 Bias RMSE R2 Bias RMSE Bondville FortPeck Goodwin Creek Penn State Sioux Falls Boulder DesertRock

26 Impacts of improved PAR products on calculating gross primary productivity (GPP) GLASS ISCCP Princeton 6 radiation products Same model for ECWMF MERRA NCEP calculating GPP in-situ measurements at 12 sites in China GLASS radiation product produces the best GPP values Cai, W., W. Yuan, S. Liang, et al., (2014), Improved Estimations of Gross Primary Production Using Satellite-derived Photosynthetically Active Radiation, Journal of Geophysical Research Biogeosciences, doi: /2013JG002456

27 Figure 7. Annual mean GPP estimates of 2008 and 2009 driven by six radiation products: The grayscale image in each plot is the standard deviation of the annual GPP.

28 Phase II GLASS products (Dec Nov. 2016) 1. Incident shortwave radiation 2. Incident PAR 3. Broadband albedo 4. Broadband emissivity 5. Longwave net radiation 6. All wave net radiation 7. Skin temperature 8. Evapotranspiration 9. Leaf area index 10. Fraction of absorbed PAR by green vegetation 11. Fraction of green vegetation coverage 12. Gross primary productivity

29 Summary Long-term high-quality satellite products are essential in detecting and assessing global environmental changes Global LAnd Surface Satellite (GLASS) products with unique features have been extensively validated Sample products and the pdf files of the papers are in the DVD Examples are given to demonstrate that they are very useful for environmental change studies Everyone is warmly welcome to evaluate and utilize them. Web addresses of the data centers are in the booklet