# Presentation: 333683

## Overview: MODLAND Production Status, Schedule and Time Series Issues (C4 to C5 Transition)

- MODIS Land Collection 5 Workshop
- Jan. 17, 2007
- Robert Wolfe
- NASA GSFC Code 614.5

## MODIS Land Products

- _Energy Balance Product Suite_
- Surface Reflectance
- Land Surface Temperature, Emmisivity
- BRDF/Albedo
- Snow/Sea-ice Cover
- _Vegetation Parameters Suite_
- Vegetation Indices
- LAI/FPAR
- GPP/NPP
- _Land Cover/Land Use Suite_
- Land Cover/Vegetation Dynamics
- Vegetation Continuous Fields
- Vegetation Cover Change
- Fire and Burned Area

- Jan. 17, 2007 - Wolfe

## MODLAND Websitehttp://modis-land.gsfc.nasa.gov/

- Jan. 17, 2007 - Wolfe

## Level 2 Products

- Retrieved geophysical parameters at the same location and in the same format as the MODIS Level 1 instrument data
- 288 granules/day; 5 min.; approx. 2340 x 2030 km
- 250m, 500m and 1km nadir resolutions

- Jan. 17, 2007 - Wolfe

## Level 2G, 3 and 4 Products (fine resolution)

- Level 2G/3: earth-gridded geophysical parameters
- Level 4: earth-gridded model outputs
- Daily, 8-day, 16-day, 32-day, monthly and yearly products
- 10o x 10o Tiles (    )
- Sinusoidal (equatorial); 7.5, 15 and 30 arcsec. resolution (roughly 250m, 500m and 1 km)
- LAEA (sea-ice products, polar projection)

- Lambert Azimuthal Equal Area (LAEA)

- Sinusoidal

- Jan. 17, 2007 - Wolfe

## Climate modeling grid products

- Resolution: 0.05o (now) and 0.25o (previous) degrees
- Almost all products are lat/long
- sea-ice is current exception – in polar grid (snow in C5)

- (from BU – NBAR CMG – days 193-208, 2001)

- Jan. 17, 2007 - Wolfe

## Land Algorithm Dependency

- Jan. 17, 2007 - Wolfe

## MODLAND Production Details

- Jan. 17, 2007 - Wolfe

## Product Format

- Hierarchical Data Format (HDF) – Self describing file format
- Science Data Sets (SDSs) – 2D, 3D or 4D arrays
- Bit Fields – unsigned integers broken into groups of bits
- Discrete values – e.g., Snow, Cloud, etc.
- Scaled Integers – valid range, scale and offset included
- Attributes – text or other data that annotates the file (global) or arrays (SDSs)
- Metadata – ECS metadata for products (stored as attributes)
- includes QA information, date/time products acquired/produced, etc.
- .met file also contains the ECS core metadata
- some additional fields
- some fields (QA, etc.) may be updated when product distributed
- HDF-EOS Metadata (SWATH or GRID) – geometric information that relates data to specific earth locations

- Jan. 17, 2007 - Wolfe

## L2G – Multiple Observations – Simple Case

- L2G – Multiple Observations – Simple Case

- Multiple observations covering a single grid cell:
- about 50% of overlap distributed into two observations
- 25% of overlap distributed over four observations.

*Observations and grid cell are the same size and have the same orientation*

- a. About 50% Overlap

- b. 25% Overlap

- Cell

- Cell

- Distribution of coverage for each of the observation with the largest intersection with a cell

- Jan. 17, 2007 - Wolfe

## L2G Format

- L2G product with same

- spatial dimensions as

- corresponding L3 tile

- Stack of

- observations per

- output grid cell

**Observation**

** **

***i***

** **

- Pointer information:

*granule pointer,*

*line, sample, etc.*

- Geophysical parameters:

- e.g.,

* **land surf. reflectance,*

*thermal anomalies, etc.*

- Viewing geometry:

*view zenith,*

*solar zenith*

*, **etc.*

- obs 3

- obs 1

- obs 2

- o

- bs

*i*

- Jan. 17, 2007 - Wolfe

## MODIS Land Collections

*Each collection represents an improvement in science quality*

- Reprocessing

- Forward processing

- C*n* – Collection Version *n*

- 2000

- 2001

- 2002

- 2003

- 2004

- 2005

- 2006

- 2007

- Provisional

- Beta

- Validated (Stage 1-2)

- Jan. 17, 2007 - Wolfe

## Land Collection 5 production schedule

- Terra-only interval reprocessing starts
- Terra and Aqua C5 forward processing started
- Complete Terra-only interval from Feb. ’00 to June ’02 (26 months @ 3X)
- Terra and Aqua reprocessing starts
- Complete year of combined products available
- Complete Aqua and Combined products from July ’02 to Dec ’06 (108 months @ 7X)

- Sept. 2006
- Jan. 2007
- May 2007
- June 2007
- Sept. 2007
- Sept. 2008

- Jan. 17, 2007 - Wolfe

## MODIS Land Collection 5 Changes – Summary

- Used improved Land/Water mask and new Land Cover map based on 3 years of Collection 4 data
- Refined surface reflectance by adopting a dynamic aerosol model in atmospheric correction
- Reduced size and complexity of daily surface reflectance products
- Improved quality of the Land Surface Temperature by revising the day/night algorithm and improving the detection and filtering of cloud contaminated observations
- Increased resolution of BRDF/Albedo products to 500m
- Refined LAI/FPAR LUTs to improve numerical accuracy of the radiative transfer simulations
- Added fractional snow algorithm in the snow product
- Burned area product added
- Improved ancillary data interpolation to remove artifacts in the NPP product
- Reduced size of all Land products through HDF internal compression

- Jan. 17, 2007 - Wolfe

## Land C5 Reduced Product Volume

|  | MODAPS Production (GB/day) |  | Export Volume (GB/day) |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  |  |  | LP DAAC |  | NSIDC DAAC |  |
|  | C4 | C5 | C4 | C5 | C4 | C5 |
| L2 – L3 Daily | 456 | 140 | 265 | 31 | 7 | <1 |
| Level 3 8-day + | 23 | 26 | 70 | 19 | 1 | <1 |
| Total | 479 | 166 | 335 | 50 | 8 | 1 |

*Reduced size of all Land products through HDF internal compression*

- Jan. 17, 2007 - Wolfe

## C4 to C5 Transition

- C5 data products are produced using the latest available versions of the science algorithms developed by the MODIS Land Science Team
- changes to fix known problems
- C5 science improvements
- C5 product format may have changed from the C4
- C5 product quality both at the pixel level and the granule level may differ from the C4
- It take 13⁄4 years to complete the remaining C5 reprocessing
- until that time, the full data record will not have been processed into either C4 or C5
- So – caution should be used if combining C5 and C4 products
- science team members will make specific recomendations

- Jan. 17, 2007 - Wolfe

## C4 vs. C5 Example – VI 

- Jan. 17, 2007 - Wolfe

## Collection 6?

- We may not need to reprocess all products for C6
- A C6 reprocessing could incorporate
- improvements in calibration and geolocation accuracy
- essential improvements to science products
- changes to product format
- recent and new MODIS science products (e.g., Burned Area, MODIS water product)
- new merged products from multiple instrument (e.g., MODIS & MISR)
- C6 would most likely not start until
- after C5 reprocessing completes (Sept. ‘08)
- until a recompeted science team (round 3) develops and tests any improvements – C5 took more than 2 years
- The breakout sessions tomorrow will give users an opportunity to discuss with the science team what C6 changes are needed

- Jan. 17, 2007 - Wolfe

## http://modis-land.gsfc.nasa.gov/

- Questions?

- Jan. 17, 2007 - Wolfe