Snow Cover activities at DLR: TIMELINE snow cover product and Global - PowerPoint PPT Presentation

Snow Cover activities at DLR: TIMELINE snow cover product and Global SnowPack Andreas Dietz, Land Surface Team Land Surface Dynamics

TIMELINE TIMe Series Processing of Medium Resolution Earth Observation Data assessing Long -Term Dynamics In our Natural Environment • 30 – year time series with AVHRR land and atmosphere products • Enable change detection analyses and the identification of geoscientific phenomenons and trends • Enhancing our ability to automatically process mass data • Simple user-access / download possibilities for the time series L1b/L2 L0 L3 Develop AVHRR time series of geo-scientific variables in the context of ‚global change‘

AVHRR data at DFD • Data since the early 80s • Three AVHRR sensors: AVHRR/1: 4 bands, AVHRR/2: five bands, AVHRR/3: six bands HRPT scenes at DFD noaa-19 noaa-18 7000 noaa-17 6000 noaa-16 noaa-15 5000 noaa-14 4000 noaa-12 noaa-11 3000 noaa-10 2000 noaa-9 noaa-8 1000 noaa-7 0 noaa-6 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012

TIMELINE variables and processing scenario Lo Stitching L0 Stitching Type Variables Pre Processing Pre processing Reflectance Brightness temperature Radiative variables Apollo NG Albedo processor Stage 1 processing Land Surface Temperature Atmospheric Water mask Vegetation variables (NDVI, LAI, FAPAR, FVC) Correction processor Processor Burnt areas Land surface „Hot Spots“ Snow / Sea Ice NDVI processor processor Water mask Cryosphere Snow and Ice over land, Sea Ice Stage 2 processing LAI processor Cloud coverage Thermodynamic cloud phase FVC Cloud top temperature Atmosphere Cloud height Cloud optical depth Stage 3 processing Surface Burnt Area Hot Spot processor Albedo processor Temperature FAPAR processor processor processor Precipitation potential

L1b-Preprocessing (L1b-Pre): Responding to extended user requirements Base AVHRR preprocessing TIMELINE AVHRR preprocessing Offline Online Online Offline: Just calibration sites System correction and System correction and Adaptation of navigation parameter base calibration base calibration Conversion from technical albedo to apparent TOA Calibration site reflectance extraction Data quality checks Spectral normalization Chip matching Radiometric harmonisation Orthorectification Quality layer generation Generation of harmonisation factors CF, ACDD, and EOP- conform metadata NetCDF + xlm-File + Harmonisation factors Quicklooks TIMELINE L1b product

L1b-Pre: Geometry a) SeaSpace TerraScan: Application of orbit model with coastline matching b) Chip-matching: A generic correction tool for imprecise geolocation Not produced Poor quality Reduced quality Good quality Clouds act as Lat/Lon- limiting factor, correction therefore: 3-step vector definition Resulting shifts Quality assessment c) Ortho: A generic correction tool for location errors due to relief impact Newton- Raphson Example showing an uncorrected RGB of an orbit segment and a colour coded shift distance “before and after” the correction Schematic overview of Newton- Raphson method

TIMELINE Snow cover processor Round robin with: ESA GlobSnow algorithm, MODIS snowmap, Canadian SPARC, APOLLO Snow-detection algorithm => The final processor is still under development Water- LST ECMWF b4 - SPARC Score mask LST ECMWF B_Score combination

Global SnowPack • Based on MODIS daily snow cover products MOD10A1 and MYD10A1 • (version 5) • 500m spatial resolution • Daily snow cover information • Products: Snow cover duration, Late and early season snow cover duration • Consistent since 2000 • Processing of AVHRR time series under development (1km spatial resolution, daily data since ~ 1985 available for some regions only)

Global SnowPack

Global SnowPack

Global SnowPack