The MODIS Land Cover Product MODIS Land Cover

The MODIS Land Cover Product MODIS Land Cover Team Boston University GLC 2000 – “FIRST RESULTS” WORKSHOP JRC – Ispra, 18 -22 March 2002

Terra Launch on December 18, 1999

MODIS Land Bands

MODIS Land Cover Product • Objective: – Provide a simple land-cover categorization for biophysical parameterization for GCM, hydrologic, and carbon cycling models

MODIS Land Cover Product: Features – Categorizes land cover according to life-form, cover and height of dominant vegetation type following IGBP-DIS scheme – Uses data from spectral and temporal domains – Relies on advanced classifier technology—i. e. , decision trees—in a supervised classification mode – Network of global test sites used for algorithm calibration and validation – At-launch 1 -km database derived from AVHRR heritage – Level 3, 1 -km spatial resolution, 96 -day product; Climate Modeler’s Grid (1/4°) product

Recent Global Land Cover Products • Beta Product, released April 15, 2001 – Based on 2 16 -day periods of Normalized BRDF-Adjusted Reflectance (NBARs) • Provisional Product 2001001, released June 15, 2001 – Based on 9 16 -day periods of NBARs within July 11– January 15, 2001 – Uses prior probabilities to help separate agriculture and natural vegetation – Includes IGBP classification, secondary classes, confidence measures – Draws from at-launch product when only 0– 2 views are available or when classification confidence is less than 40%

Recent Global Land Cover Products, Cont. • Validated Product – Due 15 April 2002 – Based on MODIS data from 2001 – Includes 4 sets of labels, per-pixel confidence measures, second choices

IGBP Land Cover Units (17) • Natural Vegetation (11) – Evergreen Needleleaf Forests – Evergreen Broadleaf Forests – Deciduous Needleleaf Forests – Deciduous Broadleaf Forests – Mixed Forests – Closed Shrublands – Open Shrublands – Woody Savannas – Grasslands – Permanent Wetlands • Developed and Mosaic Lands (3) – Croplands – Urban and Built-Up Lands – Cropland/Natural Vegetation Mosaics • Nonvegetated Lands (3) – Snow and Ice – Barren – Water Bodies

The Land Cover Input Database • Surface Reflectance – Nadir-adjusted surface reflectance, 7 land bands • Vegetation Index – MODIS Vegetation Index, maximum value composite • Spatial Texture from 250 -m Band 2* – Standard deviation-tomean ratio in Band 2 (near -infrared), maximum value composite in 32 -day period *To be added later • Snow Cover* – MODIS Snow Cover Product, number of days with snow cover • Land Surface Temperature* – MODIS Land Surface Temperature, maximum value composite • Directional Information* – Bidirectional reflectance model choices from BRDF product • Ancillary Data – DEM, * Land/Water mask

Global Composite Map of Nadir BRDF-Adjusted Reflectance (NBAR) April 7– 22 2001 no data No data True color, MODIS Bands 2, 4, 3 10 km resolution, Hammer-Aitoff projection, produced by MODIS BRDF/Albedo Team MODLAND/Strahler et al.

MODIS Nadir BRDF-Adjusted Reflectance May 25–June 9 2001 False Color Image NIR–Red–Green

NBAR Time Trajectories

MODIS 500 m Vegetation Indices (September 30 – October 15, 2000 NDVI MOD 13 A 1 16 day Composite EVI MODLAND/Huete et al

Test Sites • IGBP-DIS Core/Confidence Sites – Random stratified sampling of classes on 1992 -93 IGBP Global Land Cover Product – 425 sites identified; 413 SPOT and TM scenes acquired; 91% migrated to WWW by BU • BU STEP Database – 2614 training sites from 645 TM scenes (6/6/00) – About 1000 training sites in current use for supervised classification

DISCover Core Validation Sites

Supplemental BU Training Sites

STEP Database • STEP: – System for Terrestrial Ecosystem Parameterization • Key STEP Parameters – Life form, height, cover fraction, of layers – Leaf type, phenology, periodicity, physiognomy of dominants in layers – Elevation, moisture regime, perturbation – Classifications: IGBP, BU, EDC SLCRs – Simple description of site and type (words) • STEP Flexibility – Allows application of many different land cover labeling schemes by inference of label from parameters in database

MODLand Support Products • Six Biomes for LAI / FPAR Algorithm – Used by Ranga Myneni’s radiative transfer model in retrieving LAI and FPAR • Six Biomes for Net Primary Productivity (NPP) – Used by Steve Running’s Biome-BGC model in making the MODIS NPP product • Fourteen Classes—University of Maryland Legend – We also provide a 14 -class product using the University of Maryland scheme – Preferred by some modelers

Provisional Land Cover Product June 01

Northeast Provisional Land Cover Product, Jul 00–Jan 01 Evergreen Needleleaf Forest Agriculture Mixed Forest Agriculture/Natural Vegetation Mosaic Urban Deciduous Broadleaf Forest

Classification Confidence Map Second Most-Likely Class

Land Cover Validation • Statistical Assessment Based on Site Data – Cross-validation provides probability estimate for errors of omission/commission • Two sets of site data: – DISCover Core/Confidence sites—Random stratified sample based on DISCover Land Cover map (Loveland et al. , EDC) – Supplemental sites compiled at BU—no explicit sampling design, but large N

Validation: Accuracy Assessment • Classification Accuracy from Cross. Validation of Training Sites – Hide 20 percent of training sites, classify with remaining 80 percent; repeat five times for five unique sets of all sites – Provides “confusion matrix” – Not a stratified random sample, but a good within-class indication of accuracy

Confusion Matrix Global Test Site Confusion Matrix—Provisional Product

Per-Pixel Confidence Output • Per-pixel Confidence – Based on statistical “boosting” theory – Allows decision-tree classifier to estimate probability of classification associated with each possible class label – Output for label with highest probability for each pixel

Validation: Other Datasets • Comparison with Community Benchmark Datasets – Global (e. g. , DISCover, UMd from AVHRR) • Comparison with independent maps derived from high resolution data, e. g. , – Humid Tropics: Landsat Pathfinder – Forest Cover: FAO Forest Resources Assessment – Western Europe: CORINE – United States: USGS/EPA MLRC – United States: California Timber Maps (Mc. Iver and Woodcock)

Validation: Comparisons • Collaborative Comparisons – Big. Foot sites – MODLand Test Sites

Big. Foot Results Reprojection of Big. Foot UTM maps to ISIN

Conclusions • MODIS Land Cover Product – – Draws on AVHRR heritage Utilizes improved data and techniques Top-down, globally-consistent approach Validation plan emphasizes multiple approaches to build confidence – “Validated” product to be released about 15 April 2002 based on 2001 data