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

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

TIMELINE

Develop AVHRR time series of geo-scientific variables in the context

• f ‚global change‘

L1b/L2 L0 L3

AVHRR data at DFD

• Data since the early 80s
• Three AVHRR sensors: AVHRR/1: 4

bands, AVHRR/2: five bands, AVHRR/3: six bands

1000 2000 3000 4000 5000 6000 7000 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012

HRPT scenes at DFD

noaa-19 noaa-18 noaa-17 noaa-16 noaa-15 noaa-14 noaa-12 noaa-11 noaa-10 noaa-9 noaa-8 noaa-7 noaa-6

TIMELINE variables and processing scenario

Type Variables Radiative variables Reflectance Brightness temperature Albedo Land Surface Temperature Land surface Vegetation variables (NDVI, LAI, FAPAR, FVC) Burnt areas „Hot Spots“ Water mask Cryosphere Snow and Ice over land, Sea Ice Atmosphere Cloud coverage Thermodynamic cloud phase Cloud top temperature Cloud height Cloud optical depth Precipitation potential

Pre processing Apollo NG processor Atmospheric Correction Processor Water mask processor NDVI processor FAPAR processor Snow / Sea Ice processor LAI processor FVC Surface Temperature processor Hot Spot processor Albedo processor Burnt Area processor L0 Stitching

Lo Stitching Pre Processing Stage 1 processing Stage 2 processing Stage 3 processing

L1b-Preprocessing (L1b-Pre): Responding to extended user requirements

TIMELINE L1b product

Online

System correction and base calibration

Offline

Adaptation of navigation parameter

Online

System correction and base calibration Calibration site extraction CF, ACDD, and EOP- conform metadata Chip matching Quality layer generation Orthorectification Data quality checks

Offline: Just calibration sites

Conversion from technical albedo to apparent TOA reflectance Spectral normalization Radiometric harmonisation Generation of harmonisation factors NetCDF + xlm-File + Quicklooks Harmonisation factors

Base AVHRR preprocessing TIMELINE AVHRR preprocessing

L1b-Pre: Geometry

Not produced

Reduced quality Good quality

Lat/Lon- correction

3-step vector definition Quality assessment Resulting shifts

b) Chip-matching: A generic correction tool for imprecise geolocation

Newton- Raphson

Schematic overview of Newton- Raphson method

Example showing an uncorrected RGB of an orbit segment and a colour coded shift distance “before and after” the correction

c) Ortho: A generic correction tool for location errors due to relief impact a) SeaSpace TerraScan: Application of orbit model with coastline matching

Clouds act as limiting factor, therefore:

TIMELINE Snow cover processor

Water- mask SPARC B_Score LSTECMWF b4 - LSTECMWF Score combination

Round robin with: ESA GlobSnow algorithm, MODIS snowmap, Canadian SPARC, APOLLO Snow-detection algorithm => The final processor is still under development

• 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

• nly)

Global SnowPack

Global SnowPack

Global SnowPack

Global SnowPack