Global Land Cover Classification Based on Microwave Polarization and Gradient Ratio (MPGR) - Geoinformatics for Intelligent Transportation - page 19

Table 1 MODIS land cover classes with their code
0 Water 09 Savannas

1 Evergreen needle leaf forest 10 Grasslands

2 Evergreen broad leaf forest 11 Permanent wetlands

3 Deciduous need leaf forest 12 Croplands

4 Deciduous broad leaf forest 13 Urban built-up

5 Mixed forest 14 Cropland natural vegetation mosaic

6 Closed shrub lands 15 Snow Ice

7 Open shrub lands 16 Barren Sparsely Vegetated

8 Woody savannas

2 Data Used

The Advanced Microwave Scanning Radiometer (AMSR-E) was deployed on the
NASA Earth Observing System (EOS) polar-orbiting Aqua satellite platform. The
AMSR-E sensor measures vertically (V) and horizontally (H) polarized BT at six
frequencies (6.9, 10.7, 18.7, 23.8, 36.5, and 89.0 GHz) at a constant Earth incidence
angle of 55

from nadir. In this study, we use AMSR-E level 2A product
(AE_L2A), and the daily 25 km resolution global Equal Area Scalable Earth
(EASE) Grid BT provided by the National Snow and Ice Data Center (NSIDC).
AMSR-E is a successor to the Scanning Multi-channel Microwave Radiometer
(SMMR) and SSM/I instruments,

°

first launched in 1978 and 1987, respectively.
AMSR-E provides global passive microwave measurements of terrestrial, oceanic,
and atmospheric variables for investigation of the global water and energy cycles.
MODIS land cover data (MCD12Q1) was acquired from the NSIDC and used to
determine land cover information. The MODIS land cover type product contains
classi cation schemes, which describe land cover properties derived from obser-

vations spanning a year

'

s input of Terra data. The primary land cover scheme

identi ned by the international Geosphere Biosphere

Programme (IGBP), including 11 natural vegetation classes, 3 developed and
mosaicked land classes, and 3 non-vegetation classes (Table 1 ).

es 17 land cover classes de

3 Methodology

The derivation of microwave polarization ratio (PR) and gradient ratio (GR) is
based on the radiance transfer theory as follows:

B f ðÞ ¼2hf 3 = c 2 e hf = kT 1

ð 1 Þ

2

Þ n

2 1

B f T ðÞ ¼ 2kT =k = 1 þ ð hf = kT Þþ ð hf = kT Þ þþ ð hf = kT ð 2 Þ