Transcript ITD0350 geoland

geoland
R&D Status report
Core Service bio-geophysical Parameter
Issue I.1.00
Ralf Lindau
UniBonn
CSP Meeting
9th September 2005
geoland - CSP
Soil Moisture Retrieval for 2004
 Global soil moisture
fields for the second
year (2004) are ready.
 Resolution
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Half degree (50 km)
10 days
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CSP Meeting, Lisbon, 9th September 2005
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Duero Basin
 Time series for one grid
point in Spain during
2003/2004.
 Two years of data are now
available for the TUW
comparison in the Duero
Basin.
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CSP Meeting, Lisbon, 9th September 2005
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Two-step Retrieval
 Longterm local mean of soil moisture (85.4 % of the total variance)
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Longterm mean of precipitation
Soil texture
Vegetation density
Terrain slope
 Remaining anomaly against the longterm local mean

AMSR brightness temperatures (18 GHz, as 10 GHz is corrupted by RFI)
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CSP Meeting, Lisbon, 9th September 2005
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Calibration of local longtime means by Russian data
 Local longtime means of soil
moisture comprise the majority of soil
moisture variance (85.4%)
 Local longtime means can be
retrieved with high accuracy (r=0.854)
from:
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Climatological rain
Vegetation density
Soil texture
Terrain slope
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CSP Meeting, Lisbon, 9th September 2005
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Validation with Illinois Data
•
On global scale the Illinois
data set represents
practically only one single
site.
•
However, this spot is
retrieved accurately, lying
on the 1-to-1 line.
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CSP Meeting, Lisbon, 9th September 2005
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Chinese Soil Moisture Data
 40 Stations
 Measurements of 1m soil
moisture for the period
1981 - 1999
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CSP Meeting, Lisbon, 9th September 2005
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Validation with Chinese Data
•
Underestimation of the
mean soil moisture by
74mm. (200 mm / 274 mm)
•
Correlation low with 0.523
•
Mainly due to four desert
stations.
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CSP Meeting, Lisbon, 9th September 2005
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So far the validation of the longtime means (which include the
majority of variance).
To improve the temporal performance, the availability of lower
frequencies would be helpful, but they are disturbed by RFI.
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CSP Meeting, Lisbon, 9th September 2005
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Radio Frequency Interference
In Europe the 10 GHz channel is
completely noisy in England and Italy.
In the USA the 6 GHz measurements
are corrupted over New York, Boulder etc.
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CSP Meeting, Lisbon, 9th September 2005
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Monthly 10 GHz Time Series
250 K
300 K
• RFI is detectable by
• high monthly averages
• high monthly stddev.
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CSP Meeting, Lisbon, 9th September 2005
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Identification of RFI
Sea ≈ 90 K
Land ≈ 250 K
Coast : Transition with high
standard deviation.
RFI
: Warmer than land.
Increased stddev.
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CSP Meeting, Lisbon, 9th September 2005
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Spatial averaged TB over land
RFI is warmer than the
normal land
temperature.
We need to know the
normal TB for each
region.
Monthly averages over
an area of 10° x 30°
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CSP Meeting, Lisbon, 9th September 2005
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Simple scheme for RFI identification
•
TB
> 260 K
•
Stddev
>
•
DTB
> 20 K
compared to a 10° x 30°
surrounding
5K
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CSP Meeting, Lisbon, 9th September 2005
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Next actions
 Delivery of source codes
 Delivery of soil moisture data for 2004
 Improvement of the RFI indentification scheme and
development of a RFI correction scheme to make the lower
frequencies of AMSR usable.
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CSP Meeting, Lisbon, 9th September 2005