For Rachel Pinker, the new attendee and featured speaker of this

meeting, Ken Mitchell briefly reviewed the purpose, status, and

roles of participants in the LDAS project.

II. Briefing on Status of NCEP's Realtime LDAS Forcing

Curtis Marshall of NCEP/EMC presented a briefing on the status of

NCEP's realtime hourly, 1/8-th degree LDAS forcing.

-- a 48-hour Eta forecast backup is now executing to cover occasional

skipped cycles in the Eta 4-D Data Assimilation System (EDAS)

-- the above double serves as 48-hour forecast forcing for those who

want to test a forecast component to LDAS

-- next forcing upgrade tasks will be:

--- add an hourly zenith angle weighting to the temporal interpolation

of 3-hourly EDAS solar insolation to the hourly LDAS times

(EDAS insolation only used as a back-up to hourly GOES insolation)

--- add an elevation correction to air temperature, specific humidity,

surface pressure, and downward longwave radiation to account for

EDAS versus LDAS elevation differences

III. Briefing on Status of NCEP's driver for the NCEP LSM (aka NOAH LSM)

Dag Lohmann of NCEP/EMC provided a walk-through of his source code

for his driver program for the NOAH LSM execution in the realtime

LDAS environment. This source code serves as an example that the

wider LDAS community can follow in constructing their respective

driver's for their participating LSMs.

IV. Briefing on the GOES/GEWEX surface radiation suite

The featured presentation of the day was given by Rachel Pinker, of

the Department of Meteorology of the University of Maryland. Rachel

gave an extensive presentation of her GCIP-supported collaboration with

Dan Tarpley of NESDIS/ORA to produce realtime 0.50 degree, hourly,

surface solar insolation (and a wide host of related products) from the

GOES satellites. Rachel reviewed her a) retrieval product list, b)

features of her retrieval algorithms, c) quality control steps, and

d) product validation.

Three product streams are supported:

1) immediate realtime at NESDIS/ORA (within the hour)

2) near realtime at U. Maryland (within 24 hours)

3) historic

The NESDIS/ORA web site for stream 1) is

http://orbit-net.nesdis.noaa.gov/goes/gcip/

The U.Maryland web site for streams 2) and 3) is

http://metosrv2.umd.edu/~srb/gcip/project.htm

Rachel described the quality-control procedures that are invoked in

streams 2) and 3) above (but cannot be invoked in the immediate

realtime stream). Some discussion ensured as to the feasibility of

adding some of the QC steps to stream 1).

In the historic stream 3), Rachel's group provides instantaneous,

hourly averages, daily averages, and monthly averages.

Rachel reviewed her extensive GOES/GEWEX product list, comprised of

71 separate fields. Of these 71 products, 14 are currently included

in her long term archive, but additional choices (to within reason)

can be added to the archive upon request.

The current proposed "strawman" list of GOES/GEWEX products to be

archived for the LDAS project include

- surface downward solar insolation (total and diffuse)

- surface downward PAR (total and diffuse)

- surface skin temperature

- fractional cloud cover

- TOA cloud albedo

- TOA clear albedo

- column precipitable water (from Eta/EDAS)

- target means in T1, T2, T4, and T5

- target standard deviations in T1 and T4

- snow cover

In the realtime NCEP processing of LDAS 0.50 degree, hourly forcing,

NCEP currently proposes to include the following GOES/GEWEX radiation

products

- total surface downward insolation (which is sum of direct and diffuse)

- diffuse surface downward insolation

- total surface downward PAR

- diffuse surface downward PAR

- skin temperature

At a near-future LDAS meeting, after participants have a chance to

further ponder and digest the above two strawman lists, the LDAS

group needs to revisit and finalize the above two lists.

V. Status of LDAS Soils Database

Qingyun Duan presented the virtually completed preparation by the

Office of Hydrology of the extensive soils database needed by the

LDAS project on the LDAS grid. He showed color map displays of the

soil texture types over the LDAS grid, as well as tables of soil

texture definition and proposed soil parameters. Finally, he showed

the results of his very intriguing study of the extent of correlation

between soil texture and vegetation type. Notably, little significant

correlation was found over the LDAS national domain.

VI. Status of LDAS Streamflow Routing Code

Dag Lohmann presented examples of his ongoing development of a common

LDAS streamflow routing algorithm. He first developed a 1-degree

version which he demonstrated with some surrogate gridded runoff

inputs. He then discussed his plans and anticipated terrain data

sources to produce a 1/8-th degree streamflow routing code that will

be applied directly to 1/8-th degree LDAS gridded runoff.

In the follow-on discussion, it was decided that Dag would

1 - get the 1/8-th degree LDAS routing connectivity files from

the U.Washington/Princeton.U VIC consortium

2 - obtain the following from John Schaake's OH GCIP group:

-- basin boundaries

-- basin pixels

-- basin stream gauge observations for streamflow validation

John Schaake agreed to provide initial basin choices for testing at

the next LDAS Meeting (May 10, 1999). It was requested that these

proposed test basins be listed in a priority order per each RFC.

VII. Demonstration of the LDAS Product Realtime Image Generator (RIG)

Brian Cosgrove of NASA/GSFC gave a presentation of the Realtime

Product Generator (RIG) graphics utility being developed by GSFC for

realtime use by all LDAS participants. The RIG can be accessed

through the GSFC LDAS web-site and it has a wide array of choices of

fields to display, time looping, etc. Brian demonstrated the RIG

capability by, among other things, displaying a comparison of MOSAIC

and EDAS ground heat flux.

VIII. Next LDAS Monthly Meeting

1:30 pm, May 10, 1999, at NASA/GSFC.