About Data Extractor

About MM5 Data Extractor

Contents
About
How-To
    Extracting Data
    Saving Files
    Filenames
    File Format
Troubleshooting
More Information
    MM5 Initialization Models
    Forecast Hours
    Data Parameters
    Pressure Dependent Data Parameters
    Pressure Levels
    Latitude & Longitude Grids

About
The MM5 Data Extractor retrieves atmospheric parameters from MM5 binary output files. The output files are created twice a day by the University of Washington's Atmospheric Sciences Department using 00Z and 12Z global model runs for initialization.

How-To

Extracting Data
In order to extract data, you must select:

one or more MM5 Initialization Models
one or more Forecast Hours (taus)
a domain

36km -- data points are spaced 36km apart
12km -- data points are spaced 12km apart

a dimension

grid -- returns a grid of data.

A 36km domain returns a grid of dimension 126x150.
A 12km domain returns a grid of dimension 99x102.
You may also select a subset of the grid data by changing the Grid Indicies values. The entire grid is extracted by default.

point -- returns the parameter values interpolated to the latitude and longitude specified in the Point Position box.

A 36km domain ranges have corners (clockwise from NW)

53.01N 175.69E
63.78N -87.05E
24.44N -104.99E
18.98N -155.12E

A 12km domain ranges have corners (clockwise from NW)

51.28N -132.42E

51.61N -114.27E

40.71N -115.56E

40.43N -130.38E

Latitude and longitude values are expected to be fractions of a degree (not degrees, minutes and seconds).
Longitudes west of the meridian are negative.

one or more Data Parameters and/or Pressure Dependent Data Parameters
a Date Range -- starting and ending dates
one or more Hours (00Z and 12Z)
click the "Submit" button

Clicking the submit button will begin the extraction process. Small data sets will return almost immediatley while larger data sets will take a while to process. When the extraction is complete, a page will be loaded into your browser listing the files that were created and the status of the file: "OK" or "No Data Available".

Saving Files
There are two ways to copy the extracted data to your local machine (specifics will vary from browser to browser).

Click the link. In the browser's "File" menu, choose "Save As".
Right click or link and choose "Save Target As"

Filenames
Grid Extraction
File names are created from the date (4 digit year, 2 digit month, 2 digit day, 2 digit hour), model, domain, parameter, level (if the parameter is pressure dependent), forecast hour and either the ranges of rows and cols requested or the latitude and longitude requested -- YYYYMMDDHH-model-dx-param_level-forecasthour-rowMin-rowMaxXcolMin-colMax. For example, a file named 2002103100-cent-d1-PSFC-48-1-126x1-150 is for 31 October 2002 00Z, centroid model, 36km domain, surface pressure, forecast hour 48, full grid. (Note: d1 = 36km domain, d2 = 12km domain.)
Point Extraction
File names are created as for Grids except the requested latitudes and longitudes are included -- YYYYMMDDHH-model-dx-param_level-forecasthour-latitudeN_longitudeE_(rowMin-rowMax x colMin-colMax). For example, a file named 2002103100-cent-d1-PSEALVLC-00-45.0N_-121.0E_(38-38x65-65) is for 31 October 2002 00Z, centroid model, 36km domain, sealevel pressure, forecast hour 00, latitude 45.0N, longitude -121.0E (which corresponds to row 38 and column 65).

File Format
Files consist of a single line of data; values are space delimited. The data values are written to the file in the following order (row,col):
(1,1) (1,2) (1,3) ... (2,1) (2,2) (2,3) ... (126,1) (126,2) (126,3) ... (126,150)

Troubleshooting

I clicked submit, but the page just reloaded. Why?

You must have missed a field or given improper values for the grid dimensions or point location. Look for red highlights on the page indicating the fields that need attention.

I clicked submit and, 2 minutes later, the page is still trying to load. Why is it taking so long?

You have probably asked for data spanning a large date range. Just be patient, there are many files to read through.

I extracted some data yesterday, but when I tried access the link today, the file was gone. Where did it go?

Files are deleted after 24 hours to make room for new files. Reextract the data.

I tried to extract some data but the extractor said "No Data Available". Why isn't the data available?

Sometimes the MM5 file simply doesn't exist because MM5 wasn't run on that date or the initialization model wasn't available to set the boundary conditions, or the output was corrupt for some other reason. Some parameters aren't available for all forecast hours (look at the parameter table for more details). In fact, many parameters are not available at forecast hour 00.

I really want to look at the surface data (wind & temperature) for forecast hour 00. Why isn't it available?

This data is not contained in the files we get from the Atmospheric Scieneces Department. At 00h all data is derived from the large-scale model analyses (80-100km grid size) and interpolated to a 36km or 12km grid. 2m and 10m surface data do not exist until after the model has run through its first time step. However, even after the first time step the data is still "large-scale". It can take several time steps before the data loses it large-scale smoothness and begins to show sensitivity to the higher resolution terrain and land use information.

Note to Mac Users: You may have some difficulty viewing the extracted data files. The best solution to this problem is to right click on the link and select the save option.

More Information

MM5 Initialization Models

Model Name	Description	Maintainer
avn	Global Forecast System (GFS); formerly known as the aviation run (AVN)	U.S.A. National Centers for Environmental Prediction (NCEP)
cmcg	Global Environmental Multi-scale (GEM) model	Canadian Meteorological Centre (CMC)
eta	Eta limited-area mesoscale model	U.S.A. National Centers for Environmental Prediction (NCEP)
gasp	Global AnalysiS and Prediction (GASP) model	Australian Bureau of Meteorology (BoM)
jma		Japanese Meteorological Agency (JMA)
ngps	Navy Operational Global Atmospheric Prediction System	Fleet Numerical Meteorological and Oceanographic Center (FNMOC)
tcwb	Global Forecast System	Taiwan Central Weather Bureau (CWB)
ukmo	Unified Model	UK Met. Office (UKMO)
cent	Multi-analysis centroid (mean of the 8 models listed above)	UW Atmospheric Sciences
cent1.1a	AVN-MM5 mirrored across CENT-MM5 C1.1A = CENT + Pf * ( CENT-AVN ); Pf = 1.134	UW Atmospheric Sciences
cent1.1c	CMCG-MM5 mirrored across CENT-MM5 C1.1C = CENT + Pf * ( CENT-CMCG ); Pf = 1.134	UW Atmospheric Sciences
cent1.1e	ETA-MM5 mirrored across CENT-MM5 C1.1E = CENT + Pf * ( CENT-ETA ); Pf = 1.134	UW Atmospheric Sciences
cent1.1g	GASP-MM5 mirrored across CENT-MM5 C1.1G = CENT + Pf * ( CENT-GASP ); Pf = 1.134	UW Atmospheric Sciences
cent1.1j	JMA-MM5 mirrored across CENT-MM5 C1.1J = CENT + Pf * ( CENT-JMA ); Pf = 1.134	UW Atmospheric Sciences
cent1.1n	NGPS-MM5 mirrored across CENT-MM5 C1.1N = CENT + Pf * ( CENT-NGPS ); Pf = 1.134	UW Atmospheric Sciences
cent1.1t	TCWB-MM5 mirrored across CENT-MM5 C1.1T = CENT + Pf * ( CENT-TCWB ); Pf = 1.134	UW Atmospheric Sciences
cent1.1u	UKMO-MM5 mirrored across CENT-MM5 C1.1U = CENT + Pf * ( CENT-UKMO ); Pf = 1.134	UW Atmospheric Sciences
plus01	Same ICs as AVN but uses a different valid version of MM5	UW Atmospheric Sciences
plus02	Same ICs as CMCG but uses a different valid version of MM5	UW Atmospheric Sciences
plus03	Same ICs as ETA but uses a different valid version of MM5	UW Atmospheric Sciences
plus04	Same ICs as GASP but uses a different valid version of MM5	UW Atmospheric Sciences
plus05	Same ICs as JMA but uses a different valid version of MM5	UW Atmospheric Sciences
plus06	Same ICs as NGPS but uses a different valid version of MM5	UW Atmospheric Sciences
plus07	Same ICs as TCWB but uses a different valid version of MM5	UW Atmospheric Sciences
plus08	Same ICs as UKMO but uses a different valid version of MM5	UW Atmospheric Sciences

For more information on the initialization models look at UW Atmospheric Sciences MM5 web site http://www.atmos.washington.edu/~emm5rt/mem_summary.html.

Forecast Hours
Range from 0 - 48 in 3 hour intervals.

Data Parameters

Extractor Parameter Name	File Parameter Name	Units	Staggering	Description
SST	TSEASFC	K	cross	Sea Surface Temperature -- values only available for 00 forecast hours.
SLP	PSEALVLC	Pa	cross	Sea Level Pressure -- derived from surface pressure and adjusted to sea level.
Surface Pressure	PSFC	Pa	cross
Bulk Richardson Number	OUTBR	dimensionless	cross	Indicator of boundary layer turbulence -- incorproates bouyant energry (CAPE) and vertical shear of horizontal winds.
2m Temperature	T2	K	cross
Max 2m Temperature	MAXT2	K	cross
Min 2m Temperature	MINT2	K	cross
2m Mixing Ratio	Q2	kg/kg	cross	Amount of water in a parcel of air (kg H₂O/kg air).
Max 10m Wind Direction	MAXWDIR10	degrees	cross
Max 10m Wind Speed	MAXWSP10	m/s	cross
10m U Wind Component	U10	m/s	cross	Zonal or eastward wind speed
10m V Wind Component	V10	m/s	cross	Meridional or northward wind speed
Total Precipitation	RAINTOT	cm	cross
Ceiling	CEILING	m	cross	cloud ceiling height
Visibility	VIS	m	cross	Near surface visibility distance.

Pressure Dependent Data Parameters

Extractor Parameter Name	File Parameter Name	Units	Staggering	Description
Geopotential Height	H	m	cross	height of pressure level
Mixing Ratio	Q	kg/kg	cross	water content of an air parcel
Temperature	T	K	cross	temperature at pressure level
U Wind Component	U	m/s	dot	zonal or eastward wind speed
V Wind Component	V	m/s	dot	meridional or northward wind speed

Pressure Levels

850mb
700mb
500mb
300mb

Latitude & Longitude Grids

36km Domain (d1)

Cross Staggering
Latitude
Longitude

Dot Staggering
Latitude
Longitude

12km Domain (d2)

Cross Staggering
Latitude
Longitude

Dot Staggering
Latitude
Longitude