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37 operational BSRN stations
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Part IStatus of BSRN: database and FTP file archive
April 27, 2005 CEOS/ WGCV/Land Product Validation Workshop
on Albedo Products, Vienna
Andreas Roeschreas Institute for Atmospheric and Climate Research, ETH Zurich
• Current status of the database
• Synop/ Radiosounding
• Albedo (reflected SW radiation)
• UV/AOD (Aerosol optical depth)
• FTP file archive
37 operational BSRN stations
Operational BSRN stations (North America)
Operational BSRN stations (Europe)
Status of BSRN database
NOAA
ARM
SURFRAD
Status of BSRN database
Status, ff.
13 BSRN stations with SYNOP measurements (logical record 1000, tables STA_SYNOPBAS_YEAR and STA_SYNOPEXT_YEAR)
Station State/ Country Acronym Period of record
Barrow Alaska BAR 1992-2003
Bermuda CO, USA BER 1992-2003
Boulder USA BOU 1992-2003
De Aar South Africa DAA 2000-2004
Georg v. Neumayer Antarctica GVN 1992-2002
Kwajalein Marshall Islands, USA KWA 1992-2003
Ny Alesund Spitsbergen, Norway NYA 1992-2002
Payerne Switzerland PAY 1992-2003
Sede Boqer Israel SBO 2003
South Pole Antarctica SPO 1992-2003
Syowa Antarctica SYO 1994-2001
Tamanrasset Algerie TAM 2000-2001
Tateno Japan TAT 1996-2004
18 BSRN stations with radiosonde measurements
1992-2002: BAR, BER, BOU, GVN, KWA, NYA, SPO
1994-2004: BIL
1995-2003: BON, BOS
1996-2003: PAY
1996-2004: TAT
1997-2004: E13, MAN
1998-2003: DRA
1998-2004: NAU
2000-2004: DAA
2003: SBO
BSRN stations reporting 10m-observation to BSRN (logical record 3010, table „STA_RMH1000_YEAR“)
Station State/ Country Acronym Organisation Period of record
Bondville IL, USA BON SURFRAD 1995-2003
Boulder CO, USA BOS SURFRAD 1995-2003
Desert Rock NV, USA DRA SURFRAD 1998-2003
E13 USA E13 ARM 1997-2004
Fort Peck MT, USA FPE SURFRAD 1995-2003
Goodwin Creek MS, USA GCR SURFRAD 1995-2003
Payerne Switzerland PAY Swiss meteo 1994-2003
Rock Springs PA, USA PSU SURFRAD 1998-2003
All these stations provide reflected SW radiation and thus surface albedo
BSRN stations reporting reflected SW radiation(at standard height)
Station State/ Country Acronym Organisation Period of record
Barrow Alaska, USA BAR NOAA/ CMDL 01/1992 - 11/1993
Ny Alesund Spitsbergen, Norway NYA AWI, Germany 08/1992 - 12/2003
South Pole Antarctica SPO NOAA/ CMDL 01/1992 - 12/2003Georg v. Neumayer Antarctica GVN AWI, Germany 04/1992 -12/2003
Syowa Antarctica SYO NIPR, Japan 04/1998 - 01/2002
Payerne Switzerland PAY Meteo Swiss 03/1992 - 04/2004
Toravere Estonia TOR Est. Met. Inst. 01/1999 - 03/2004
Tateno Japan TAT Jap. Met. Agency 02/1996 - 01/2004
BSRN stations reporting UV to BSRN (logical record 500, table „STA_RMUV_YEAR“)
Station State/ Country Acronym Organisation Period of record
Boulder CO, USA BOS SURFRAD 1995-2003Goodwin Creek MS, USA GCR SURFRAD 1995-2003
Fort Peck MT, USA FPE SURFRAD 1995-2003Bondville IL, USA BON SURFRAD 1995-2003Rock Springs PA, USA PSU SURFRAD 1998-2003Desert Rock NV, USA DRA SURFRAD 1998-2003Momote, Manus Is.
Papua New Guinea MAN ARM 1996-2004
Nauru IslandTropical Western Pacific
NAU ARM 1998-2004
Payerne Switzerland PAY Swiss meteo 1998-2003Toravere Estonia TOR EMHI 2000-2001
Payerne provides both direct and diffuse UV-a and UV-b, all others only provide total UV-b
BSRN stations measuring UV, not reporting to BSRN
Station State/ Country Acronym Organisation Period of record
Tateno Japan TAT From 1990
Syowa Antarctica SYO From 1991
Alice Springs Australia ASP BoM From 1993
Chesapeake Virginia, USA CHL NASA
Tamanrasset Algerie TAM From 1997
Georg von Neumayer Antarctica GVN From 1992
Lauder New Zealand LAU NIWA From 1991
From B. Forgan, based on information from station scientists (at the request of Ohmura/ Roesch)
BSRN stations planning to measure UV radiation
Station State/ Country Acronym Organisation
Camborne UK CAM MetOffice
Lervick UK LER MetOffice
From B. Forgan, based on information from station scientists
Aerosol optical depth (AOD) in BSRN
Current status: No station provides spectral shortwave radiation (record 200 or 400) Only GVN and NYA includes record 1300 (but provides missing values for spectral AODs)
Future plan:
Database: Insertion of computed AOD values (for 3 wavelengths) into record 1300 only after transmission data have passed several consistency checks.
-> No change in the database schema is required.-> Block 1300 is excluded from the instrument consistency checks.
File archive: All measured and calculated data (at all wavelengths) are included in the ftp file archive, including QC/ QA
FTP file archive (ftp://ezksun3.ethz.ch)
Motivation • Most scientists are more familiar with file archives than with databases • The web interface does not allow the retrieval of all data• Access and download via file archive is simple and fast• Can be easily modified (value-added data)
Current status The file archive is automatically updated (cron-job) every night -> The database and the file archive generally contain identical data.
Differences between the database and the file archive• Improved quality check flags (recommended by Ells Dutton and Chuck Long)• Global radiation „global1“ added (sum diffuse plus direct SW radiation)
Format Compressed ASCII-files (use „gunzip“ to uncompress data)
FTP file archive - some details to the format
Format is the same as described in the „Update of the Technical plan for data management (1998)“ but with the following extensions: • Logical record 100 line 1: X, I1, X, I1, X, I1, X, I1
Global radiation: Physically possible, extremely rareDirect radiation: Physically possible, extremely rare
line 2: X, I1, X, I1, X, I1, X, I1, X, I1, X, I1, X, I1, X, I1
Diffuse radiation: Physically possible, extremely rareLongwave downward rad. : Physically possible, extremely rareGlobal radiation: Comparison between „global 1“ and „global 2“Comparison between diffuse and direct radiationComparison of longwave downward and 2m- temperature
FTP file archive - some details to the format (ff)
• Logical record 300 Extension to each line: X, I1, X, I1, X, I1, X, I1, X, I1, X, I1, X, I1, X, I1
LW upward radiation: Physically possible, extremely rareReflected SW radiation : Physically possible, extremely rareGlobal radiation: Comparison between reflected SW and global radiationComparison of LW up to air temperatureLW up to LW down comparison
Meaning of the quality flags2 -> suspected to be erronous5 -> cannot be performed9 -> passed the procedure
Conclusions (Part I)• The BSRN database currently contains 37 operating stations with a total of
approximately 2950 monthly data files.
• Number of stations which report
SYNOP: 13
Radiosounding: 18
UV: 10
Albedo: 15
• More and more scientists prefer to download data from the FTP file archive.
• The FTP file archive is automatically updated from files that have been successfully inserted into the BSRN database.
• The FTP file archive includes the quality flags according to E. Dutton and C. Long as well as „global 1“ (computed from direct and diffuse measurements).
• Data in the FTP file archive can be easily modified/ extended.
Part II
Some applications of MODIS/ BRDF data
Validation of seasonal cycles of surface albedo in ECHAM4 and ECHAM5
Masks
Annual cycles of surface albedo
Sub-grid scale variability
and
how representative are point measurements?
Correlation of MODIS 0.05x0.05 surface albedo with PAY pixel (2000-2003)
PAYPAY
ZHBS
BON
MODIS versus ground truth from BSRNMODIS versus ground truth from BSRN
Surface albedo: MODIS vs. BSRN
Data from Greenland summit have been kindly provided by Sebastian Hoch, ETH Zurich
Zenith angle dependence of surface albedo
Black sky albedo, 6-21 March 2002, Resolution: 0.5o
Solar angle at local solar noon
MODIS white sky albedo minus black sky albedo
VIS: blue
NIR: red
Conclusions (Part II)• MODIS/ BRDF provides high-quality data for validation of GCMs and
improving their parameterizations
• MODIS (at 0.05 resolution) agrees well with ground truth from BSRN sites during snow-free periods. Under snow conditions, deviations are significant due to differing vegetation cover (-> snow masking of forest).
• MODIS Version 4 differs from Version 3 (in both the mean and the MODIS Version 4 differs from Version 3 (in both the mean and the variability)variability)
• MODIS Version 3 is too low over pure snow such as Greenland (Version 4 provides improved data).
• ECHAM4 surface albedo is too high over boreal forests and the Himalayas/ Tibetan Plateau.
• ECHAM5 is closer to the observations over the Himalayas than ECHAM4, but positive albedo biases over snow-covered boreal forests are even more pronounced in ECHAM5.
Conclusions (ff)• MODIS & BSRN clearly show that neglecting the zenith angle dependence
leads to significant errors in the net shortwave radiation. The approach of Briegleb et al. (1986) is suggested for land surface albedo models.
• Intracell variability of surface albedo is largest in snow-covered areas and deserts. Normalized intracell variances are largest in mountainous regions.
• Intracell variability in the VIS spectrum is much higher than in the NIR band over (partially) snow covered regions (difference snow - ,no snow is also higher in the VIS)
• Surface albedo at specific sites are generally representative for a limited Surface albedo at specific sites are generally representative for a limited area only.area only.
Correlation of MODIS surface albedo with 0N/65W pixel (rain forest)