Google Earth Engine ——MODIS表面反射率产品提供了在没有大气散射或吸收的情况下在地面测量的表面光谱反射率的估计。低层数据经过了大气气体和气溶胶的校正-阿里云开发者社区

The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption. Low-level data are corrected for atmospheric gases and aerosols. MOD09GA version 6 provides bands 1-7 in a daily gridded L2G product in the sinusoidal projection, including 500m reflectance values and 1km observation and geolocation statistics.

Documentation:

MODIS表面反射率产品提供了在没有大气散射或吸收的情况下在地面测量的表面光谱反射率的估计。低层数据经过了大气气体和气溶胶的校正。MOD09GA第6版在正弦投影的每日网格化L2G产品中提供了1-7个波段，包括500米反射值和1公里观测和地理位置统计。

文件。

用户指南

算法理论基础文件(ATBD)

一般文件

Dataset Availability

2000-02-24T00:00:00 - 2021-09-19T00:00:00

Dataset Provider

NASA LP DAAC at the USGS EROS Center

Collection Snippet

Copied

ee.ImageCollection("MODIS/006/MOD09GA")

Bands Table

Name	Description	Min	Max	Resolution	Units	Wavelength	Scale
num_observations_1km	Number of observations per 1K pixel	2	127	1000 meters			0
state_1km	Reflectance data state QA			1000 meters			0
state_1km Bitmask	Bits 0-1: Cloud state 0: Clear 1: Cloudy 2: Mixed 3: Not set, assumed clear Bit 2: Cloud shadow 0: No 1: Yes Bits 3-5: Land/water flag 0: Shallow ocean 1: Land 2: Ocean coastlines and lake shorelines 3: Shallow inland water 4: Ephemeral water 5: Deep inland water 6: Continental/moderate ocean 7: Deep ocean Bits 6-7: Aerosol quantity 0: Climatology 1: Low 2: Average 3: High Bits 8-9: Cirrus detected 0: None 1: Small 2: Average 3: High Bit 10: Internal cloud algorithm flag 0: No cloud 1: Cloud Bit 11: Internal fire algorithm flag 0: No fire 1: Fire Bit 12: MOD35 snow/ice flag 0: No 1: Yes Bit 13: Pixel is adjacent to cloud 0: No 1: Yes Bit 14: BRDF correction performed data 0: No 1: Yes Bit 15: Internal snow mask 0: No snow 1: Snow
SensorZenith	Sensor zenith angle	0	18000	1000 meters	Degrees		0.01
SensorAzimuth	Sensor azimuth angle	-18000	18000	1000 meters	Degrees		0.01
Range	Distance to sensor	27000	65535	1000 meters	Meters		25
SolarZenith	Solar zenith angle	0	18000	1000 meters	Degrees		0.01
SolarAzimuth	Solar azimuth angle	-18000	18000	1000 meters	Degrees		0.01
gflags	Geolocation flags			1000 meters			0
gflags Bitmask	Bits 0-2: Fill 0: Fill Bit 3: Sensor range validity flag 0: Valid 1: Invalid Bit 4: Digital elevation model quality flag 0: Valid 1: Missing/inferior Bit 5: Terrain data validity 0: Valid 1: Invalid Bit 6: Ellipsoid intersection flag 0: Valid intersection 1: No intersection Bit 7: Input data flag 0: Valid 1: Invalid
orbit_pnt	Orbit pointer	0	15	1000 meters			0
granule_pnt	Granule pointer	0	254	1000 meters			0
num_observations_500m	Number of observations	0	127	500 meters			0
sur_refl_b01	Surface reflectance for band 1	-100	16000	500 meters		620-670nm	0.0001
sur_refl_b02	Surface reflectance for band 2	-100	16000	500 meters		841-876nm	0.0001
sur_refl_b03	Surface reflectance for band 3	-100	16000	500 meters		459-479nm	0.0001
sur_refl_b04	Surface reflectance for band 4	-100	16000	500 meters		545-565nm	0.0001
sur_refl_b05	Surface reflectance for band 5	-100	16000	500 meters		1230-1250nm	0.0001
sur_refl_b06	Surface reflectance for band 6	-100	16000	500 meters		1628-1652nm	0.0001
sur_refl_b07	Surface reflectance for band 7	-100	16000	500 meters		2105-2155nm	0.0001
QC_500m	Surface reflectance quality assurance			500 meters			0
QC_500m Bitmask	Bits 0-1: MODLAND QA bits 0: Corrected product produced at ideal quality - all bands 1: Corrected product produced at less than ideal quality - some or all bands 2: Corrected product not produced due to cloud effects - all bands 3: Corrected product not produced for other reasons - some or all bands, may be fill value (11) [Note that a value of (11) overrides a value of (01)] Bits 2-5: Band 1 data quality, four bit range 0: Highest quality 7: Noisy detector 8: Dead detector, data interpolated in L1B 9: Solar zenith ≥ 86 degrees 10: Solar zenith ≥ 85 and < 86 degrees 11: Missing input 12: Internal constant used in place of climatological data for at least one atmospheric constant 13: Correction out of bounds, pixel constrained to extreme allowable value 14: L1B data faulty 15: Not processed due to deep ocean or clouds Bits 6-9: Band 2 data quality, four bit range 0: Highest quality 7: Noisy detector 8: Dead detector, data interpolated in L1B 9: Solar zenith ≥ 86 degrees 10: Solar zenith ≥ 85 and < 86 degrees 11: Missing input 12: Internal constant used in place of climatological data for at least one atmospheric constant 13: Correction out of bounds, pixel constrained to extreme allowable value 14: L1B data faulty 15: Not processed due to deep ocean or clouds Bits 10-13: Band 3 data quality, four bit range 0: Highest quality 7: Noisy detector 8: Dead detector, data interpolated in L1B 9: Solar zenith ≥ 86 degrees 10: Solar zenith ≥ 85 and < 86 degrees 11: Missing input 12: Internal constant used in place of climatological data for at least one atmospheric constant 13: Correction out of bounds, pixel constrained to extreme allowable value 14: L1B data faulty 15: Not processed due to deep ocean or clouds Bits 14-17: Band 4 data quality, four bit range 0: Highest quality 7: Noisy detector 8: Dead detector, data interpolated in L1B 9: Solar zenith ≥ 86 degrees 10: Solar zenith ≥ 85 and < 86 degrees 11: Missing input 12: Internal constant used in place of climatological data for at least one atmospheric constant 13: Correction out of bounds, pixel constrained to extreme allowable value 14: L1B data faulty 15: Not processed due to deep ocean or clouds Bits 18-21: Band 5 data quality, four bit range 0: Highest quality 7: Noisy detector 8: Dead detector, data interpolated in L1B 9: Solar zenith ≥ 86 degrees 10: Solar zenith ≥ 85 and < 86 degrees 11: Missing input 12: Internal constant used in place of climatological data for at least one atmospheric constant 13: Correction out of bounds, pixel constrained to extreme allowable value 14: L1B data faulty 15: Not processed due to deep ocean or clouds Bits 22-25: Band 6 data quality, four bit range 0: Highest quality 7: Noisy detector 8: Dead detector, data interpolated in L1B 9: Solar zenith ≥ 86 degrees 10: Solar zenith ≥ 85 and < 86 degrees 11: Missing input 12: Internal constant used in place of climatological data for at least one atmospheric constant 13: Correction out of bounds, pixel constrained to extreme allowable value 14: L1B data faulty 15: Not processed due to deep ocean or clouds Bits 26-29: Band 7 data quality, four bit range 0: Highest quality 7: Noisy detector 8: Dead detector, data interpolated in L1B 9: Solar zenith ≥ 86 degrees 10: Solar zenith ≥ 85 and < 86 degrees 11: Missing input 12: Internal constant used in place of climatological data for at least one atmospheric constant 13: Correction out of bounds, pixel constrained to extreme allowable value 14: L1B data faulty 15: Not processed due to deep ocean or clouds Bit 30: Atmospheric correction performed 0: No 1: Yes Bit 31: Adjacency correction performed 0: No 1: Yes
obscov_500m	Observation coverage percent	0	100	500 meters			0
iobs_res	Observation number in coarser grid	0	254	500 meters			0
q_scan	250m scan value information			500 meters			0
q_scan Bitmask	Bit 0: Scan of observation in quadrant 1 [-0.5 row, -0.5 column] 0: No 1: Yes Bit 1: Scan of observation in quadrant 2 [-0.5 row, +0.5 column] 0: No 1: Yes Bit 2: Scan of observation in quadrant 3 [+0.5 row, -0.5 column] 0: No 1: Yes Bit 3: Scan of observation in quadrant 4 [+0.5 row, +0.5 column] 0: No 1: Yes Bit 4: Missing observation in quadrant 1 [-0.5 row, -0.5 column] 0: Different 1: Same Bit 5: Missing observation in quadrant 2 [-0.5 row, +0.5 column] 0: Different 1: Same Bit 6: Missing observation in quadrant 3 [+0.5 row, -0.5 column] 0: Different 1: Same Bit 7: Missing observation in quadrant 4 [+0.5 row, +0.5 column] 0: Different 1: Same

使用说明：MODIS data and products acquired through the LP DAAC have no restrictions on subsequent use, sale, or redistribution.

数据引用：

LP DAAC - MOD09A1 LP DAAC - MOD09A1

代码：

var dataset = ee.ImageCollection('MODIS/006/MOD09GA')
                  .filter(ee.Filter.date('2018-04-01', '2018-06-01'));
var trueColor143 =
    dataset.select(['sur_refl_b01', 'sur_refl_b04', 'sur_refl_b03']);
var trueColor143Vis = {
  min: -100.0,
  max: 8000.0,
};
Map.setCenter(-7.03125, 31.0529339857, 2);
Map.addLayer(trueColor143, trueColor143Vis, 'True Color (143)');

Google Earth Engine ——MODIS表面反射率产品提供了在没有大气散射或吸收的情况下在地面测量的表面光谱反射率的估计。低层数据经过了大气气体和气溶胶的校正

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