Meeting on OSSEs and Nature run

Date and Time: Thursday September 21^st^, 10am EDT

Location: WWB Room 100

Attendees:

Lars Peter Riishojgaard (LPR), Gail McConaughy (GM) , Joe Terry (JT),
Ronald Errico(RE), Juan Jusem, Zoltan Toth (ZT), Jack Woollen (JW),
Yucheng Son(YS), Jim Yoe, Michiko Masutani (MM)

VTC attendees:

Thomas W Schlatter (TWS), Steve Weygandt, Yuanfu Xie (YX), Dezso
Devenyi, Nikki Prive

Teleconference attendees:

Erik Andersson (EA) , Gert-Jan Marseille (GJM), Steve Greco (SWA)

The notes and presentation are posted at

<http://www.emc.ncep.noaa.gov/research/osse/NR/record>

> OSSE_Progress.060913.doc
>
> mtg.060921.agenda.doc
>
> NR_data_NCEP_proposal.060921.doc
>
> JT_JW_conventional.060921.doc
>
> prepdwl.Sep06.tab.060921.doc
>
> OSSE_Criteria.060921.doc
>
> OSSE_Criteria.060921.ppt
>
> Errico.060921.ppt
>
> TWS.OSSE_truth.060921.doc

Some reference materials are saved in

<http://www.emc.ncep.noaa.gov/research/osse/NR/references>

> Jung.2005.tm471.pdf
>
> KNMI.piew_finalreport.2006.pdf
>
> Lord_ams97.html
>
> Lorenc.1992.TIDCCR4129.pdf
>
> Masutani.2006.on451.pdf
>
> RJPWFA10.pdf
>
> Tompkins.2004.tm452.pdf

**Agenda for meeting on 21^st^**

> 0\. Introducing people
>
> 1\. Format of the nature run
>
> 2\. Data distribution policy of the nature run
>
> 3\. Data transfer method for the nature run
>
> 4 Selection of the period for high-resolution nature runs
>
> 5 DWL bufrtable which all participating centers will be able to use
>
> (Gert-Jan Marseille, Steve Greco and Jack Woollen)
>
> 6\. Strategies for simulation of conventional data (Joe Terry and Jack
> Woollen)
>
> 7\. Steps toward a credible OSSE (Tom Schlatter)
>
> 8\. Review future discussion items

**1. Format of the nature run**

NCEP proposed the nature run data format.
(NR_data_NCEP_proposal.060921.doc)

During the meeting most of the proposed ideas were accepted.

All data will be provided in Grib1 packing.

Model and surface data (2 dimensional data) will be in a gaussian grid.

(N256 for T511 data)

There was no strong demand for a full gaussian grid, which increases
data volume 25%. However, ZT was cautious about any mistakes and human
resources involved in the expansion process.

Pressure level data and isentropic level data will be in 1x1 regular lat
lon grids.

EA said it is possible to create 1x1 lat lon gridded data for selected
surface data variables. Suggested surface variables are attached in
Appendix A.

**2. Data distribution policy of the nature run.**

EA said as far as ECMWF is concerned, the nature run data will be made
available to the list of people interested in OSSE that was made by
Michiko last year. The list includes operational centers, research
centers and the university community.

ZT is concerned about the resources required for the distribution of the
data on US side. GM was not sure if NASA will be able to support the
data distribution, either.

EA confirmed the nature run data will be available from the ECMWF
THORPEX server. ZT reminded the group that NCAR also has a THORPEX
server.

MM contacted Dave Person of THORPEX;,he will contact NCAR to find out
the possibility of providing any support for data distribution.

**3. Data transfer method for the nature run**

ECMWF has disks that can be used for data transfer. The disks will be
sent back to ECMWF after the data is downloaded.

It may be possible to receive pressure level data by ftp. Both ECMWF and
NCEP will look into the possibility.

**4 Selection of the period for high-resolution nature runs**

EA said the frequent writing of data is the most time consuming part of
the operation. ECMWF will be able to produce one six week run with a
hourly dump or two six week runs with a three hourly data dump.

We agreed to receive one six week high resolution nature run with a
hourly dump during the hurricane season and then look into the
possibility of and necessity for the second, longer run with less
frequent data dumps.

**5 DWL bufrtable which all participating centers will be able to use**

Gert-Jan Marseille agreed to use same bufr table. KNMI and SWA will keep
in touch to maintain the common bufr table. See Appendix B for notes.

**6. Strategies for simulation of conventional data** (Joe Terry and
Jack Woollen)

JW and JT discussed about the data distribution of aircraft, satellite
wind, and dropsonde data. Since the locations of these data depend on
weather instrument system, using locations from the real observations
will cause an unrealistic data distribution.

JW emphasized that the definition of the surface is a tricky problem. If
we use the model surface in the simulation, the surface data will be too
good.

**7. Steps toward a credible OSSE** (Tom Schlatter and Ron Errico)

Tom Schlatter and Ron Errico presented prepared slides.

Slides areposted at:

> <http://www.emc.ncep.noaa.gov/research/osse/NR/record>
>
> OSSE_Criteria.060921.doc
>
> OSSE_Criteria.060921.ppt
>
> Errico.060921.ppt

MM said OSSEs by various models are very valuable. Traditionally, people
thought an OSSE must be done by models which are very different from the
model used for the nature run. OSSEs using twin or cousin models have
been criticized. However, OSSEs using close relative models may provide
valuable information as a reference.

JJ mentioned that anomaly correlation depends on the climatology used.

**8. Review future discussion items**

The next meeting will be on November 16^th^.

Topics:

Review initial diagnostics of the nature run

Strategies of diagnostics and evaluation metric

Simulation of radiance data

**9. Note on representativeness error**

Ron Errico will summarize the discussion on representativeness error.
Please send your notes to Ron Errico. Send Michiko a copy that she can
keep as a record. When the note is ready it will be distributed to the
OSSE-NR group and a meeting will be scheduled.

**Appendix A:**

Selection of surface data which will be sent in 1x1 lat-lon. It may be
too much to make 1x1 data for entire surface data. We may have to select
variables.

Just as a reference the variables included in old T213 nature run are:

ID Abbrev Unit Parameter

139 ST K Surf.temp/soil temp lev 1

(from 930804)

141 SD m Snow depth

(of water equivalent)

151 MSL Pa Mean sea level pressure

164 TCC (0 - 1) Total cloud cover

165 10U m s\*\*-1 10 metre u wind component

166 10V m s\*\*-1 10 metre v wind component

167 2T K 2 metre temperature

168 2D K 2 metre dewpoint temperature

173 SR m Surface roughness

174 AL - Albedo

176 SSR W m\*\*-2 s Surface solar radiation\*

177 STR W m\*\*-2 s Surface thermal radiation\*

178 TSR W m\*\*-2 s Top solar radiation\*

179 TTR W m\*\*-2 s Top thermal radiation\*

180 EWSS N m\*\*-2 s East/West surface stress\*

181 NSSS N m\*\*-2 s North/South surface stress\*

186 LCC (0 - 1) Low cloud cover

187 MCC (0 - 1) Medium cloud cover

188 HCC (0 - 1) High cloud cover

235 SKT K Skin Temperature

Now precipitation is available. We do need surface height.

Joe Terry said if he has to choose one he wants Mean Sea-Level Pressure.

Since volume of the data is small, we decide it is easier to save all
available surface data in 1x1 degree grid.

**Appendix B: Collaboration between KNMI and SWA, DWL bufrtable**

9/21/2006

From Gert-Jan Wrote

If I understand correctly, SWA coordinates the DWL simulation. We did
the DWL simulation for the ADM-Aeolus OSSE in 2000, but you have your
own simulation tool. I guess we should figure out which DWL scenarios to
simulate and how to integrate our simulation tools. Is there a plan
already in this respect ?\
\
With respect to the BUFR template we might consider the option of having
two HLOS wind profile solutions for each location, i.e. one from the Mie
(aerosol) channel and one from the Rayleigh (molecular) channel. At this
stage it is not clear how to process the combined information from both
channels into one wind solution. To keep things flexible we could
archive both solutions in BUFR.

9/21/2006

Steve Greco Wrote

I was glad that it was pointed out that pressure, u and v were
diagnostic values and not derived form the lidar. One error I did note
on the SWA-NCEP DWL BUFR table is that ELEV is Elevation Angle and not
ELevation. For the rest, we should be able to work with KNMI.

10/12/06

Michiko pointed out that Station ID and TYP (Observation type) are
missing in current DWL bufrtable. In the meeting of technical staffs,
Jack Woollen suggested that DWL should be treated like satellite data.
Therefore we will not need Station ID and TYP, instead we need satellite
ID. This will allow DWL data from various satellites.

**Appendix C: Representativeness error**

There were lively E-mail communication about representativeness errors
following the E-mail by Gert-Jan. Ron Errico agreed to put together
lecture on representativeness error with Tom Schlatter. The summary of
the discussion, note from KMNI, list of references are posted from
nature run web site.

http://www.emc.ncep.noaa.gov/research/osse/NR/RepE

If you have any comments please send E-mail to Ron Errico, Tom Schlatter
and CC to myself. I will include you in the E-mail list.

**Appendix D. Shipping the data and distribution of the data**

500mb and 1000mb geopotential height, convective and large scale
precipitation in 1x1 degree grid were made available to NASA-NOAA OSSE
group. 500mb and 200mb U and V, SLP will be posted as well.

ECMWF need to know the list of the users.

Michiko will maintain two lists of users

A. List of people who have access to the complete data set sent to NCEP
which copies will be send to NASA/GSFC and ESRL.

B. List of people who have access to sample pressure data posted at
Nature run website.

Update of the list will be sent to ECMWF.

First four month of the data was send to US on November 15^th^.