Hurricane Andrew, Aug 1992

MERRA Stream 2 has completed through 1993. We have been looking at various weather and climate events. Hurricane Andrew was a powerful, but fairly small hurricane. MERRA's 1/2 degree resolution is likely too coarse to adequately resolve the circulation, and there is no bogus or center relocation being done in the system. Still, assimilation of observations will show some circulation or feature.

There isn't much of a circulation prior to landfall in Southern Florida. Landfall was at 9Z24Aug1992. Figure 1 shows the sea level pressure and wind barbs from 6Z the closest analysis time before landfall. The pressure center is much higher than the observed center pressure (955 mb). the center of the pressure is located south of the best track at that time. The feature that really attracted attention is the offset of the wind circulation, even further south than the pressure center, and crossing the isobars at the center.

Figure 1 MERRA Sea Level Pressure and 1000 mb wind barbs from the 6Z 24 AUG92 analysis. The blue line shows the best track befre and after landfall, with red markers at 00Zs.

A closer look at the observations being assimilated shows that ERS1 did track over the center of circulation around 6Z. Figure 2 shows all the observations accepted into the analysis. There are ERS1 wind vectors crossing the center of the circulation, and the assimilation system accepted the data. The vectors closest the center are likely contaminated by precipitation, and should have been rejected. At this point, it's not clear how often this kind of problem occurs, or what might be done to detect and reject the bad data. It's under investigation.
An important point for reanalysis users, especially as resolutions are increased to better resolve weather and smaller scale circulations, is that reanalyses are assimilating vast quantities of observations. sometimes poor quality data does make it into the analyses. While quality of data and analyses are improving, users still need to consider that features may or may not be realistic. Likewise, we are providing some information on the accepted observations in MERRA. More difficult is providing access to the users on the actual observations.

Figure 2. MERRA analysis sea level pressure, analysis streamlines and windbarbs showing the accepted observations (red is buoy or ship, black is ERS1). Most of the ERS1 vectors seem to agree with the mass field, however, close to the center of the low pressure the ERS1 vectors are crossing the isobars. The wind analysis is drawing to the observations, even when they disagree with the mass field.

Initial Data Available

This is a short note to inform you that the first years of data have been opened for access at the Modeling and Assimilation Data and Information Services Center (MDISC). The announcement can be found here: http://gmao.gsfc.nasa.gov/research/merra/data_access.php

Instructions for download and visualization are available at: http://disc.sci.gsfc.nasa.gov/MDISC/

Documentation and status of the system and data files are at the MERRA WWW page: http://gmao.gsfc.nasa.gov/merra/

While there are a number of tools for access, to download large amounts, probably the most straightforward way is to follow the links through Mirador (a search and order program). This will provide a script that will ftp the data back to the user. Alternately, Mirador can provide pointers to the ftp location of the data, which can also be copied with "wget".

Keep in mind that the data is not yet a complete time series. Links to production status are provided above. However, there is a lag between production and data availability at MDISC required for quality checking of the data files.

If you do download data, please be sure to sign up to the MERRA news listserv at the MDISC site. As issues related to the scientific understanding of the data and system become known, we will make every effort to communicate this information to users. The listserv is the most direct way to contact users.

We are also forming a FAQ list and citation lists. The content of these are directly related to users providing information back to the GMAO.

MERRA turns 11, Global Energy Budget

Last week, MERRA had produced 11 years of data across all 3 streams (79-82, 89-92 and 98-00). Here is a quick evaluation of the global energy budget so far. The reference values are a recent update from Trenberth et al. (2009, BAMS accepted DOI: 10.1175/2008BAMS2634.1). There is a difference between MERRA and this reference, where MERRA is averaging all 11 years, while the reference data was developed from theory as well as observations and reanalyses from March 2000 - May 2004. MERRA is presently in 2001, so it will be a couple months before we can reproduce the global energy budget for this exact time.

(In the figure, MERRA data includes 130 months written in red)

At the surface, too much shortwave, and not enough longwave reach the surface, while at the top of the atmosphere, too little shortwave is reflected and too much longwave is emitted. This suggests that the cloud fraction is too low or cloud optical properties too thin (or both). It is interesting to note that the values tend toward improving in time toward the 2000s. A discussion on the trends in the global energy budget is being prepared.

Some other interesting features occur. The overestimate of the shortwave energy (primarily over the ocean) into the surface is not translating into increased sensible, latent or upward longwave fluxes. Instead, it contributes to the imbalance at the surface, and since the SSTs are prescribed the surface is not warming. Also, the difference of precipitation and evaporation reflect the influence of hte analysis increments on the water budget (globally taking water out of the system).

Trenberth et al (linked above) provide more discussion on the global budget, as well as comparisons to the NCEP and JRA reanalyses.

Severe Freeze in South America

While looking over the area average time series of the Amazon River basin produced by MERRA, a very cold event was apparent in July 1981. Figure 1 shows the time series of 850 mb temperature for the basin, and the event is several K colder than earlier in the reanalysis. The cold event starts around July 16 1981, and lasts a few days. Looking at the observation reports from this period, did not show any major problems with the input obs, yet the analysis increments of water vapor show a strong shift, starting with this event (Figure 2). So, the shift in the increments along with the temperature spike suggests, at first glance, a problem. However, the lack of rejected observations or increased error in the forecast says the observation and assimilation are OK.

While considering the problem, Austin Conaty used Google Scholar to search for cold events in the Amazon. It turns out that there was a strong system pushed northward across the continent bring cold air and a freeze to Brazil (Fig 3 from Fortune and Kousky, 1983). By looking at the Amazon Basin area average, we see the cold anomaly push into the basin. While it looks out of place, it is a real feature. We'll file this under, you learn something new every day.

Figure 1 Time series of Amazon basin average 1 hourly 850 mb temperature (K) for 1979 through 1981. The July 1981 cold anomaly stands out in this relatively short time series.

Figure 2 Time series of area averaged analysis increment of water vapor daily averages (dqvdt_ana, mm/day) for the Amazon basin from May 1981 through Sept 1981. As the cold air enters the region, the analysis increments shift (becoming smaller negative values).

Figure 3 Synoptic maps of the cold air event, brining a sever freeze to Brazil, copied from Fortune and Kousky (1983, MWR).

Known Issue #1, east Atlantic anomaly

Recently, an evaluation of the global energetics identified an anomalous feature, a bullseye, off the coast of Portugal during most of 1979 and 1980. The anomaly affects many tendencies and variables in this localized region. Figure 1 shows the JJA 1979 Analysis Increments of temperature at 500 mb, the center of the strong negative increment is a persistent radiosonde that appears to be flawed, compared to other nearby sondes. However, it was not rejected by the data assimilation's quality control. The sonde itself is being researched as to whether it is mislocated or just poor quality. Regardless, 1979 and 1980 data have a localized problem. The data will still likely be made available, as other regions around the globe, and certain global parameters are not as dramatically affected. However, we will try to alert users to this issue, as it will affect any investigation of the weather in the eastern Atlantic Ocean or possible western Europe (Figure 2).

The current plan is to re-run the affected period at a later date, however, that re-run will not replace the existing data, but be placed alongside the existing data. We will continue to use and evaluate the current 1979 and 1980 data, and if other issues arise, fixes could also be incorporated into the re-run. Also, with this problem, a new page will be created for the MERRA WWW site to catalog issues with the data as they arise, and include any actions to those issues.



Figure 1 JJA 1979 analysis increments of temperature (DTDT_ANA). The questionable sonde is causing the negative increments circled.


Figure 2 Temperature differences (MERRA-JRA25) at 850 mb for JJA 1979. The low temperatures resulting from the questionable sonde are apparent west of Portugal. The featuer is also apparent in the surface pressure fields (not shown)

Integrating Earth Observations

One of the advantages of reanalyses is that many different sources of observations are combined in a global gridded consistent system. We have a brief overview of MERRA and the challenges facing reanalyses published in the online IEEE magazine Earthzine www.earthzine.org. There are a number of interesting interviews and articles at the site as well.

MERRA Short Course at AMS

We will have a short course at the AMS Annual meeting January 11 in Phoenix AZ. It will cover an overview of the system and physics, the validation that we have already done, but the most important and interesting component will include several hands on tutorials working with data online. Given that the volume of data will be quite large, the subsetting and previewing tools should be useful to researchers to target the data they require. The audience will likely be graduate students or researchers who work directly with the data. Several tools that are used regualrly at the GMAO to manipulate the data, formats and grids will be demonstrated.

The announcment is on this page: http://www.ametsoc.org/MEET/annual/call.html and the registration is currently open. The AMS will shortly publish an agenda, and we are currently working on adding more details to that regarding the tutorials.

While MERRA won't be completed by then, it will be nearly halfway complete. Also, by then data will be accessible online.

Status and File Spec

Production of MERRA data has been progressing at 10 days per day on three streams, which is what is expected. Data monitoring is going on regularly, and the system seems to be moving along at the expected data quality. We have some time series routines being run, and will report on those when we achieve 8 full annual cycles. Currently, Streams 1 and 2 have more than 2.5 years each, and stream 3 has 22 months.

The MERRA File specification document has also been updated and reflects exactly the data files being produced. The document can be found at the bottom of the MERRA home page, and a link is provided here.

MERRA mail list

A mail list has been established to pass on news and alerts regarding MERRA especially the data. Send an email to majordomo@listserv.gsfc.nasa.gov with the body of the message "subscribe merra-news"

You will receive a message with instructions to confirm the subscription.

AMS Annual Meeting - Abstract deadline Aug 1

There is a planned session on reanalyses at the AMS Annual meeting, co sponsored by the Committee on Hydrology and Climate Variability and Change Committee. The deadline is August 1. Please see the call for papers:
http://www.ametsoc.org/MEET/annual/index.html

Status July 17

Late last week, the computing platform running MERRA was brought down for scheduled maintenance including an upgrade to the operating system. When it was brought back online, numerous scripts and control jobs for MERRA were broken. The science and executables for MERRA remain, but the control of jobs and data flow needed to be patched for the new OS. At this point, the three MERRA streams are processing forward. However, some post processing scripts are still being patched, such as the information on our Production Progress and Quick View pages. Those should be back on line in a few days.

Brief Comparison with Interim Reanalysis

Recently the ECMWF Interim reanalysis has been released (see http://data.ecmwf.int/data/). We have a quick overlap and look at a comparison with MERRA at monthly time scales for January 1998.

The figure below shows two features of the MERRA system we have been tracking since the system was under development, 1) negative zonal wind bias in the tropics and extratropics and 2) dry bias in the lower troposphere, especially the tropics. These are apparent against each of the existing long reanalyses (see the quick look page for more comparisons). However, in comparing ERA40 and the new Interim reanalyses with MERRA, the magnitude of the differences is smaller compared to Interim.

At this time monthly files are not available on the ECMWF site. When those become available for download, we will integrate the Interim data into the quick look pages for comparisons.



(Gary Partyka, GMAO, downloaded the Interim data and performed the comparison and evaluation.)

Status June 15

Just a brief update. The updated sonde fixes seem to be going well. The restarted Stream 3 is into March 1998, and we have evaluated the early data. Stream 1 has completed 1979, and Stream 2 will complete 1989 in a day or so. While their has been scheduled downtime for the computing system (Discover), recent upgrades have paid off with 11 days/day of throughput per stream.

Status June 8

Streams 1 and 2 have been progressing, and full years should be available by the end of this week.

Stream 3 was held for the revision to the sonde data (station identifiers and launch times, see the May 23 post). However, it was decided to restart from January. Stream 3 is presently restarted and at Jan 11 1998.

MERRA Quick View

We've just opened a new link on the MERRA WWW page. It is a version of what our monitoring team is using to look quickly at various aspects of the circulation and water cycle. We'll be adding some other figures, like time series of the monthly data as well.

http://gmao.gsfc.nasa.gov/research/merra/prequel/view.php

Status May 23

All three runs streams are progressing forward, 5 months in, approximately. However, as some folks here were making corrections a few weeks ago there were some unusual reports in the sonde data. Further investigation has found a problem that is fairly easily correctable. Actually there are two problems, and they change in time.

Starting around 1988, the actual launch time isn't being considered, just the synoptic time of the launch. From 1988-1992, this occurs in less than 1% of the launches at any given synoptic time. After 1992, the rate increases to around 10-15%. The consensus is that the impact to the 1989 MERRA stream is small, and we can have this fixed by the time we cross 1992. However, in 1992, a more serious problem occurs. Then, some sondes are not labeled correctly as to their manufacturer. This then affects whether the radiation correction for certain sondes is called, and the radiation correction is important to handle correctly. This occurs at a rate of about 15% at any given synoptic time, also a fairly large number. Again it can be corrected for the 1989 stream, before it gets serious.

The 1998 stream is another matter. Both of these problems are occurring at a rate of about 15% per synoptic time in January 1998 and on. So, the data we have processed for the 1998 stream has a flaw than needs to be corrected. In order to stay timely with the MERRA processing, we will continue the 1998 stream to 1 July 1998, at which time the fixed sonde data will be implemented. The Jan - Jun 1998 data processed so far will not be released. Instead, we will continue the 1989 stream to recover this period, and there will be overlap through 1998 to ensure that the transition of streams is as smooth as possible.

A word about the source of this error. We are using recently reprocessed sonde data from NCEP, and working with NCEP closely on monitoring and quality controlling this data. This is the data set that would also go into the NCEP CFSRR, but is not the same as has been used in previous reanalyses.

So in summary, there is no impact on the 1979 data stream. The extremely small number of launch time errors early in the 1989 stream are considered to be nominal, and the sonde data will be fixed as soon as possible. The 1998 data from Jan - Jun must be redone. The fix to the data will be implemented on Jul 1998.

Status May 19

All three streams have progressed through March and into April of their respective first years. Evaluation of the primary diagnostics and data usage seems as expected, and these first few months have passed monitoring tests. The data has been approved for transfer to the GES DISC, where the data will be available for download.

We are still testing some of the software for accessing the data files. However, it won't be held for any significant length of time. When we get a schedule for opening the data, it will be posted on this site.

The runs seem to be going smoothly, and with throughput back near the 10 days per day level. (a good sign).

Status May 14

All three MERRA streams have been running, and past their respective first month. We have started evaluating the first months, so far no surprises. The evaluation is not yet completed. The vertically integrated budget diagnostics are fully incorporated in this version, and the online file specification document should be updated soon. The budgets are complete and deep into the terms of the equations, owing to the thoroughness of Larry Takacs and Max Suarez. We'll try to post some more information on this soon.

We still are only getting 8 days per day throughput. A planned upgrade to the computing system should improve I/O, and is expected to help regain the throughput.

Status May 2

The fixed tag of the data assimilation system has been handed off to operations. They are preparing to restart the streams. However, we found that the updated PAOBS data had a problem in 1988. A different data format has caused problems there, but not in any other
data files. The 1988 PAOBS are being reprocessed. Since this affects the start of the 1989 stream (stream 2), it will continue to hold for the data fix. Otherwise, we should see Streams 1 and 3 restart today.

Reanalysis Information and Precipitation work

The previous post on reanalysis precipitation climatology was some extra information from a paper recently accepted at the Journal of Applied Meteorology and Climatology, the pre-press version is available online at AMS. Evaluations of the GEOS5 precipitation are discussed in the last section.

More generally, the extended abstracts from the 3rd International Reanalysis Conference has been published online. See the email copied below.

begin message -----

Dear Participants

We would like to announce that the extended abstracts of oral and poster presentations at the third WCRP International Conference on Reanalysis that took place in Tokyo, Japan, 28 January- February 2008, are now available at following URL.

[World Climate Reanalysis Programme]
http://wcrp.ipsl.jussieu.fr/Workshops/Reanalysis2008/abstract.html

Thank you for your cooperation,

Best regards,

Eriko Moriai


Secretariat for WCRP International Conference on Reanalysis

Status April 24

The three streams are holding at the end of their spin up periods. Some refinements are being made to the budget output diagnostics for better closure. We have also been reviewing our input data holdings. A gap in the PAOB data set was found from 1997 through the end of 2000. The PAOB data starts back up in 2001 through our CDAS input data stream.

After checking this issue with Jack Woolen at NCEP, we found that he had just finished preparing revised PAOB data set (including about 4x more data) from 1985-2000 using JRA25 and ERA40's data holdings. In short, we are aiming to implement these data (many thanks to Jack, and counterparts at JMA and ECMWF). So, the restarts will be delays a few days to test this implementation.

For further information on PAOB, see http://www.bom.gov.au/bmrc/basic/wksp16/papers/Seaman.pdf

A consistent positive impact from the PAOB data suggests that this is worth a couple days to put into the system.

Status April 18 - Rewind

The data drop reported in the last status posting prompted some deeper digging in the input data streams. One issue led to another, then another. Briefly, a bug fix that should have been zero difference actually caused double counting in some of the input data streams, affecting the 1979 and 1989 streams. Further, a resource file had incorrect settings in the 1998 stream, leading to several observation systems not being assimilated.

The net result is that the data cannot be used as expected, and almost all the production processing needs to be re-run. The estimate for getting production restarted is Wednesday Apr 23. In addition, these errors have exposed some blind spots in our monitoring routines and adjustments are being made, and more personnel time is being devoted to monitoring.

Status Apr 15

Over the past weekend, Sondes dropped out for a day (mid-Oct 1979) from the data stream (they exist, but the something in the computing environment skipped a beat). So, on Monday AM 4/14, the 1979 stream was backed up to the previous restart before the data drop, and restarted. The monitoring team is looking for issues like this routinely.

Checkout the revised Production Progress web page. Updated regularly with the current day that is being produced.

http://gmao.gsfc.nasa.gov/research/merra/progress-events.php

Status Apr 11 - Long

There has been much going on, and a lot keeping me from these updates, unfortunately. There are several items I'll include here.

First, our late 90's "scout run" (2 degree resolution, same system as MERRA) was running well ahead of the reanalysis, but encountered a problem in a single file of MSU data. There was a corruption in the input file. it has been found and corrected. That's the benefit of these coars scout runs, they should find the problems that would otherwise slow down the processing.

The system had been running at just over 10 days per calendar day for some time. However, we have been only getting ~7 days per day lately. It's a technical problem that the computer folks are working. It basically comes down to increased usage on the machine, affecting the MERRA jobs. People are looking at it, to try to get the performance back up.

We have a monitoring routine established. Some climate maps are being inspected each month of reanalysis. (Some examples posted below) Soon we hope to make those available on the internet. The monitoring code also includes range checking on each and every variable and layer produced by the system. We have some hits in the range checking from variables SHLAND (land only sensible heat flux) and TSTAR (surface layer temperature scale). TSTAR seems to be spiking sporadically, but in conditions with low wind speed and near the change from night to day (stable to unstable) conditions. It does not appear to be a severe problem, there is no plan to stop or back up MERRA for these flags. SHLAND is showing range check errors at a few, very repeatable points. Those are where the fraction of land is much smaller than that for ocean. So, it appears that ocean is driving a surface atmosphere that is causing convergence problems in the land parameterization where the fraction of land is small. For example dry soil with a dominantly tropical ocean point. So far, the grid average sensible heat seems reasonable, so there is no immediate plans to correct this, or stop and rewind MERRA.

Range checking has also found occasional occurrences of shortwave radiation diagnostics are reporting negative numbers. The magnitude is very very small, and the result of roundoff in the interpolation, and not protecting against such negative values. The net effect of these should be extremely small, but may trip code that expects perfectly zero values of shortwave radiation components. Users will be advised to clear such negative values.

A systematic difference from other reanalyses has been occurring monthly and in each season. Below the zonal specific humidity and 850mb map of specific humidity compared to ERA40 in JJA 1979 is attached. These biases were noted in validation. The contour interval is small and the range close. The MERRA data is dry in the tropics at 85omb and wet above 700mb. This is an interesting result, considering that the total column water and precipitation have been very well reproduced.

There's more to come, including online access to figures that the GMAO is using for monitoring.

Zonal mean specific humidity for JJA 1979 compared to ERA40.
850 mb Specific Humidity for July 1979 compared to ERA40.
Global Precipitation difference of existing long reanalyses compared to GPCP (CMAP differences included for reference) for July 1979.

MERRA FAQ

We have started to put together a list of frequently asked questions regarding MERRA. Obviously, it will grow with the frequency of questions. Comments or questions posted here will also contribute to the list.

http://gmao.gsfc.nasa.gov/research/merra/faq.php

Status Mar 14

All three streams have been running, though there was some down time on the supercomputer last night. So far:

• Stream 1: 19790227
• Stream 2: 19890121
• Stream 3: 19980109
  

When the jobs are running, we get ~10 days per real day from each stream.

Status Mar 11

All three MERRA streams are running. Stream 1 has just finished Jan1979, so we'll be evaluating that tomorrow. Streams 2 and three are still in their final spin up period, but will be finished with the spin up by tomorrow.

We have a link to an image that is regularly updated and shows how much data of each stream has been produced, as well as how much data is left to produce.

http://gmao.gsfc.nasa.gov/operations/merra_status_production.gif

Needless to say, at this point we have much more to do.

Status Mar 7

All the updates are checked in and Stream 1 (starting 1979) has restarted. Streams 2 and 3 should also start soon.

Status Mar 5, Rewind

Since the last post, we found that the coefficient update being implemented (and a required fix) also affected the MSU data for TIROS-N which is the only satellite data in early 1979. Since this is a non-zero difference, we need to rewind the 1979 MERRA stream (it had progressed to the start of NOAA-6, July 1, 1979) and rerun.

While testing the updated coefficients, some zero-difference updates to the output diagnostics were incorporated to the system. The updated tag is being handed back to operations, who should be able to restart Stream 1 (1979) before the end of this week. In looking at the first 6 months of the 1979 that is being rerun, the output seems much as we expected from validation experiments.

We still have some backlog in the computing queues for other projects, and we are going to rerun our 2006 validation experiment with the updated coefficients as a formal validation of the implementation of this update. It is important to not that the model physics and generally the data assimilation has not changed in some time, and the bug fix to these coefficients are part of the input data stream.

Status Feb 15

The MERRA Stream 1 (starting Jan 1979) has been progressing steadily, up to mid March 1979. We've had a look at Jan 1979, and it looks to be within expectations. The second two streams are on hold, mainly because there are some short experiments still being run.

However, it has also come to our attention that the CRTM team are fixing a bug in the coefficients for MSU radiances. Stream 1 won't assimilate these until July 1979, but the second stream will assimilate these immediately. The hold for the short runs will continue through next week, at which time the status of the update to these coefficients will be reevaluated. However, all indications are that the reanalysis should not proceed until these are included in the CRTM. This is an interesting development. We'll run some tests of the impact of the bug fix.

So, in the mean time, we can continue the processing of the Stream 1, and evaluate it along the way. Some results will be posted in the next couple days.

Status Feb 10

One of the last few fixes included in the system (discussed in the previous update), one that should have been minimal impact, greatly affected some code in the data assimilation. The result was that many wind observations that should have been assimilated were not. The problem was apparent (actually the system crashed), so the fix has been fixed.

There have also been several down times in the last week while some updates were made to the computing platform. So far, it looks like the data stream starting in 1979 has been running continuously (or at least regularly) over the weekend. It is up to 15 JAN 1979 after starting on Friday in December 78. So, if all goes well, by Tuesday we should see the first month of MERRA data.

With all the down time, some short reprocessing experiments that the GMAO is producing for instrument team support have been delayed. So, there is a backlog that is being cleared out. Once clear, the second two streams will be restarted from Jan 1989 and Jan 1998, respectively.

Status Feb 1

The three streams are ready to start. The first has run from Jan 1 1979 to Jan 9. However, all are on hold while system maintenance is being done (in other words, the computers are down).

By Monday, I'll be back from the 3rd International Conference on Reanalyses in Tokyo Japan, with better information. It has been a very interesting meeting, with status updates from the 20th Century reanalysis project and the NCEP CFS Reanalysis and Reforecast project (see the ppt at the CFS Site). Stay tuned to these interesting activities too!

Status Jan 28

The three spinup runs reported earlier have completed 1 year of spin up. These have provided the starting points for the MERRA production. The output diagnostics have been updated to correct minor diagnostic bugs, and when the system is rebuilt, production will begin.

I'm monitoring status from the 3rd WCRP International Conference on Reanalysis, and will this page when new information is available.

Status Jan 19

A data flag was out of place, and Stream 1 had to be backed up. All are still moving forward to the end of the December of their respective spin up phases.

Stream 1 date completed: 19781202

Stream 2 date completed: 19881124

Stream 3 date completed: 19971124

The at the end of December of each stream, the system will be rebuilt one last time.
While checking the output data, several minor bugs were found in the output, but nothing that changes the physics. A few other bugs have also been found, which may be non-zero in the physics. These are present being address, but none are considered to be significant changes to the results or validation of the system.

Generally, when the system is running 10 days of reanalysis are produced every day, from each stream. This may not add up with extrapolations from recent posts, because of computer downtime, or backing up the system.

Status Jan 12

The Spin Up periods are still being processed.

• Stream 1 RUNNING at 11/01/78
• Stream 2 RUNNING at 09/26/88
• Stream 3 RUNNING at 09/27/97

A group of GMAO folks have begun a final check of consistency between the output data files and the file specification document. The group will report back next Thursday.

Status Jan 4

Over the holidays, the last few science fixes went into the system, and the spinup periods resumed. Each of the three MERRA processing streams is presently running, with the data to be discarded for spinup.

• Stream 1 RUNNING at 08/31/78
• Stream 2 RUNNING at 07/30/88
• Stream 3 RUNNING at 07/30/97

As a reminder, the planned start day for each stream is Jan 1, 1979, 1989 and 1998 respectively. They are moving at approximately 10 days per day, when the computer systems are up. They will hold at the end of each November, so that the last patch of the system (engineering fixes to the output diags, scripting and post processing that do not affect science) can be put into place. At that time, the GMAO will also make an evaluation of the output diagnostics, to ensure that the data and units all match the file spec document.

There is a known issue already becoming apparent. The CRTM coefficients for NOAA 8 AMSUA channel 14 have some problems. This data doesn't begin until May 1983, so there is time to correct the problem without affecting the MERRA production schedule. Further updates as the run get closer will be provided.

Happy New Year!