# Presentation: 201338

## Part IStatus 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 

-  37 operational BSRN stations

##  Operational BSRN stations (North America) 

##  Operational BSRN stations (Europe) 

-  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 - 12/2003 |
| Georg 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 | 1995-2003 |
| Goodwin Creek | MS, USA | GCR | SURFRAD | 1995-2003 |
| Fort Peck | MT, USA | FPE | SURFRAD | 1995-2003 |
| Bondville | IL, USA | BON | SURFRAD | 1995-2003 |
| Rock Springs | PA, USA | PSU | SURFRAD | 1998-2003 |
| Desert Rock | NV, USA | DRA | SURFRAD | 1998-2003 |
| Momote, Manus Is. | Papua New Guinea | MAN | ARM | 1996-2004 |
| Nauru Island | Tropical Western Pacific | NAU | ARM | 1998-2004 |
| Payerne | Switzerland | PAY | Swiss meteo | 1998-2003 |
| Toravere | 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 rare
- Direct 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 rare
- Longwave downward rad. : Physically possible, extremely rare
- Global radiation: Comparison between „global 1“  and „global 2“
- Comparison between diffuse and direct radiation
- Comparison 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 rare
- 	Reflected SW radiation : Physically possible, extremely rare
- 	Global radiation: Comparison between reflected SW and global radiation
- 	Comparison of LW up to air temperature
- 	LW up to LW down comparison
- 		          Meaning of the quality flags
- 			2 -> suspected to be erronous
- 			5 -> cannot be performed
- 			9 -> 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 

- 	    Annual cycles of surface albedo

## Sub-grid scale variability 

- and
- how representative are point measurements?

## Slide 25

## Slide 26

## Slide 27

## Correlation of MODIS 0.05x0.05 surface albedo with PAY pixel (2000-2003)

## PAY

**PAY**

- ZH

- BS

## Slide 30

## BON

## MODIS 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 

-    Black sky albedo, 6-21 March 2002, Resolution: 0.5o

## MODIS white sky albedo minus black sky albedo

- Solar angle
- at local solar noon

- VIS: blue
- NIR: red

## Slide 38

## 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 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 area only.

## Slide 41

## Slide 42

## Slide 43

## Correlation of MODIS  surface albedo with 0N/65W pixel (rain forest)