A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies

Figures & data

Figure 1. Hardware configuration for the GLASS product production system.

Table 1. Specifics of the hardware devices within the GLASS product production system.

Number	Name	Major equipment parameters
1	Computation server	One hundred and forty four computation nodes with a double quad-core CPU for each node; 1 GB/10 GB switch
2	Production management server	Five classes of system management servers: task management, resource monitoring, data arrangement, production scheduling, and quality inspection
3	Storage system	SAS storage: capacity 200 TB;15 krpmSAS hard disk; IOPS no less than 650 thousand; and 2 RAID cards for each IO node, totaling 24
		SATA storage: capacity 500 TB; SATA 7200 rpm hard drive; IOPS no less than 650 thousand; 2 RAID cards for each IO node, totaling 24
		Mobile disk: capacity 500 TB; SATA 7200 rpm hard drive, mainly used for data download and back-up
4	Database management server	Six classes database management servers: database management, data catalog, data security, data service, order inquiry, and data download

Figure 2. Three examples of the improved MODIS surface reflectance images using the TSCD algorithm (left) compared to the original MOD09A1 (right): (a) Amazon, (b) Java, Indonesia, (c) Bohai area of eastern Asia. All images were acquired on 28 July 2001.

Figure 3. Original AVHRR data from the NASA 0.05° long-term AVHRR data-set on 7 January 2000 (top) and the reprocessed data (bottom). Color composite using bands 1 (blue), 2 (green), and 1 (red).

Table 2. Characteristics of the five GLASS products.

Product	Spatial resolution	Temporal resolution	Temporal range
Shortwave albedo	1–5 km, 0.05°	8-day	1981–2010
Incident solar radiation	5 km, 0.05°	3-h	2008–2010
Incident PAR	5 km, 0.05°	3-h	2008–2010
Longwave emissivity	1–5 km, 0.05°	8-day	1981–2010
LAI	1–5 km, 0.05°	8-day	1982–2012

Table 3. Summary of the current global shortwave broadband albedo products.

Albedo products	Spatial resolution	Temporal resolution (day)	Temporal range
MODIS	0.5 km, 1 km, 0.05°	8–16	2010–present
GlobAlbedo	0.05°	16	1998–2011
POLDER	1/12°	10	1996.11–1997.06, 2003.04–2003.10, 2005.07–2010.08
VEGETATION (Geoland2)	0.5°	10/30	1999–present
GLASS	1–5 km, 0.05°	8	1981–2010

Figure 4. GLASS albedo product at five sites: (a) Fort_Pack, 48.3079N, −105.101E, glassland; (b) ARM_SGP_Main, 36.605N, −97.4884E, cropland; (c) Duke_forest_hardwoods, 35.9736E, −79.1004N, mixed forest; (d) Naiman_site, 42.9333E, 120.700N, desert; (e) NASA-SE, 66.4797E, −42.5002N, ice sheet.

Figure 5. Global average albedo and anomalies on land surfaces.

Figure 6. Spatial and temporal variations of global land surface albedo anomalies.

Figure 7. Global land surface monthly integrated incident PAR in 2008 at 5 km spatial resolution calculated from GLASS PAR product in (a) January, (b) April, (c) July, and (d) October.

Table 4. WMO observation requirements for surface downward shortwave irradiance by Space program. NWP: Numerical Weather Prediction, AOPC: Atmospheric Observation Panel for Climate. (http://www.wmo-sat.info/db/variables/view/50, updated on 23 June 2011).

	Uncertainty goal (W m^−2)	Uncertainty threshold (W m^−2)	Horizontal resolution goal (km)	Horizontal resolution threshold (km)
Global NWP	1	20	10	100
Agricultural meteorology	N/A	N/A	1	20
Climate-AOPC	5	10	25	100

Table 5. Summary of the current global incident shortwave radiation satellite products.

Insolation products	Spatial resolution	Temporal resolution	Temporal range
ISCCP	280 km	3-h	1983–2008
GEWEX-SRB	1°	3-h	1983–2007
CERES	140 km	3-h	1997–present
GLASS	5 km	3-h	2008–2010

Table 6. Comparison of retrieved 3 h GLASS insolation product, the International Satellite Cloud Climatology Project—Flux Data (ISCCP-FD), CERES model B, and the CALISPO, CERES, Cloudsat and MODIS (CCCM) enhanced product in 2008.

							CERES
	Retrieved DSSR			ISCCP-FD			Model B			CCCM enhanced
Site	R^2	Bias	RMSE	R^2	Bias	RMSE	R^2	Bias	RMSE	R^2	Bias	RMSE
Bondville	0.87	14.68	104.97	0.71	−7.06	149.88	0.84	12.9	119.5	0.82	−0.5	126.16
FortPeck	0.84	10.51	102.75	0.69	9.61	150.37	0.81	5.3	112.40	0.80	2.3	115.02
Goodwin Creek	0.91	−6.29	99.54	0.64	12.61	184.11	0.69	14.3	172.0	0.66	−3.8	179.35
Penn State	0.85	18.17	109.3	0.7	5.92	152.88	0.87	6.9	107.0	0.86	−8.6	111.18
Sioux Falls	0.81	11.52	114.41	0.65	37.83	168.85	0.62	−11.4	167.4	0.58	−37.8	178.77
Boulder	0.81	−12.8	126.38	0.72	6.49	154.96	0.34	−12.0	249.3	0.47	−43.0	214.41
DesertRock	0.92	−52.4	112.94	0.87	−42.4	125.27	0.52	−24.2	198.0	0.49	−26.6	206.38

Table 7. Summary of the current global spectral emissivity products. IASI: Infrared Atmospheric Sounder Interferometer.

Products	Spatial and temporal resolutions, and temporal range	Wavelengths
CERES emissivity map (Wilber, Kratz, and Gupta 1999)	Global coverage, 10′×10′, no temporal variation	12 spectral bands and one broadband (5–100 µm)
MODIS-based baseline fit database (Seemann et al. 2008)	Global coverage, 0.05°, monthly, 2003–2011	10 wavelengths (3.6–14.3 µm)
AIRS (Pequignot, Chedin, and Scott 2008)	30°N–30°S, monthly, April 2003–March 2006	3.7–14 µm (0.05 µm spectral resolution)
IASI (Capelle et al. 2012)	30°N–30°S, monthly, April 2007–March 2011	3.7–14 µm (0.05 µm spectral resolution)
ASTER (Gillespie et al. 1998)	Global discontinuous coverage, 90 m, 2000–present	5 bands
MODIS emissivity product (MOD11) (Wan and Li 1997)	Global coverage, 0.05°, 2000–present	6 bands (3.8–12.0 µm)
GLASS emissivity	Global coverage, 5 km (1981–1999) and 1 km (2000–2010)	1 broadband (8–13.5 µm)

Figure 8. Long-term global surface thermal broadband emissivity mean values for five land cover types from the GLASS emissivity product. The UW-Madison CIMSS emissivity product (narrowband emissivity values are converted into the broadband emissivity using the published formula, Cheng et al. 2012) is also presented for comparison. Land cover maps are from the MODIS product: Majority_Land_Cover_Type_1 (MCD12C1 V5) and the land cover map from 2000 is used for the mean value calculation before 2000.

Table 8. WMO observation requirements for LAI by Space program. (http://www.wmo-sat.info/db/variables/view/98, updated on 3 June 2012).

Application area	Uncertainty goal (%)	Uncertainty threshold (%)	Spatial resolution goal (km)	Spatial resolution threshold (km)	Temporal resolution goal	Temporal resolution threshold (day)
Global NWP	5	20	2	50	24-h	10
High-resolution NWP	5	20	1	40	12-h	2
Hydrology	5	20	0.01	10	7-day	24
Agricultural meteorology	5	10	0.01	10	5-day	7
Climate-TOPC	5	10	0.25	10	24-h	30

Table 9. Summary of the current global LAI products; current products do not meet the user requirements.LAI products

	LAI type	Spatial resolution	Temporal resolution (day)	Temporal range
MODIS	True	1 km	8	2010–present
CYCLOPES	Effective	1/112°	10	1999–2003
GLOBECARBON	True	1/11.2°	10	1998–2007
Geoland2	True	1 km, 0.05°	10	1981–2012
GLASS	True	1–5 km, 0.05°	8	1981–2012

Figure 9. Global average LAI for the period 1981–2012.

Figure 10. Slope of the linear fitting of global LAI changes from 1981 to 2012.

Figure 11. Temporal variations of global average LAI from 1981 to 2012 (y-axis has been multiplied by 10).

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