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Data Set ID:
NSIDC-0179

CLPX-Model: Local Analysis and Prediction System: 4-D Atmospheric Analyses, Version 1

The Local Analysis and Prediction System (LAPS), run by the NOAA's Forecast Systems Laboratory (FSL), combines numerous observed meteorological data sets into a collection of atmospheric analyses.

This is the most recent version of these data.

Version Summary:

Initial release

BASIC Level of Service

Data: Data integrity verified

Documentation: Key metadata and links to supporting documentation available

User Support: Assistance with data access and basic data usage

See All Level of Service Details

Parameter(s):
  • ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > AIR TEMPERATURE
  • ATMOSPHERIC PRESSURE > ATMOSPHERIC PRESSURE MEASUREMENTS
  • CLOUDS > CLOUD PROPERTIES > CLOUD FRACTION > Cloud Amount/Frequency
  • CLOUDS > CLOUD PROPERTIES > CLOUD BASE HEIGHT > Cloud Base
  • CLOUDS > CLOUD PROPERTIES > CLOUD CEILING
  • ATMOSPHERIC WINDS > WIND DYNAMICS > CONVERGENCE > CONVERGENCE/DIVERGENCE
  • ATMOSPHERIC WINDS > WIND DYNAMICS > DIVERGENCE > CONVERGENCE/DIVERGENCE
  • ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > DEW POINT TEMPERATURE
  • ATMOSPHERIC WATER VAPOR > WATER VAPOR PROCESSES > EVAPORATION
  • ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > HUMIDITY
  • GROUND WATER > GROUND WATER PROCESSES/MEASUREMENTS > INFILTRATION
  • SURFACE THERMAL PROPERTIES > LAND SURFACE TEMPERATURE
Data Format(s):
  • NetCDF
Spatial Coverage:
N: 42, 
S: 38.5, 
E: -104, 
W: -108.5
Platform(s):MODELS
Spatial Resolution:Not SpecifiedSensor(s):NOT APPLICABLE
Temporal Coverage:
  • 1 September 2001 to 31 August 2003
Version(s):V1
Temporal Resolution1 hourMetadata XML:View Metadata Record
Data Contributor(s):Glen Liston

Geographic Coverage

Download Via HTTPS: An Earthdata Login account is required to access these data.

Once you have logged in, you will be able to click and download files via a Web browser. There are also options for downloading via a command line or client. For more detailed instructions, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Liston, G. E. 2003. CLPX-Model: Local Analysis and Prediction System: 4-D Atmospheric Analyses, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/9TDTHSWY4KWA. [Date Accessed].

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Detailed Data Description

LAPS makes use of a wide range of observational data sets as part of its analyses, including:

  • surface observations at specific sites every 5 minutes
  • hourly surface aviation observations
  • Doppler radar volume scans every 6 minutes
  • wind and temperature Radio Acoustic Sounding System (RASS) profiles from the NOAA Demonstration Profiler Network every 60 minutes
  • GOES [Geostationary Operational Environmental Satellites] visible data every 30 minutes,
  • multi-spectral image and sounding radiance data every 90 minutes
  • automated aircraft observations.

However, the LAPS.noaa.gov is no longer available. The experimental LAPS runs were dropped from any further development in the NOAA laboratory.

Format

LAPS data files are in netCDF format. NetCDF is a general format structure. For more information on the netCDF file format, please see the NetCDF Resources at NSIDC Web site. The detailed format of each data file is self-describing (via 'ncdump'), and is mirrored in a separate static file called the CDL.

LAPS data include the following variables:

Table 1. Hourly LAPS Output Variables

File Extension

LAPS Variable

CDF Variable

Number of Levels

Field (units)

surface: LSX

U

u

1

u Component of Surface Wind (m/s) (grid north)

V

v

1

v Component of Surface Wind (m/s) (grid north)

P

p

1

1500 m Pressure (Pa)

T

t

1

Surface Temp (K)

TD

td

1

Surface Dewpoint Temp (K)

VV

vv

1

Vertical Velocity (m/s)

RH

rh

1

Relative Humidity (%)

MSL

msl

1

MSL Pressure (Pa)

TAD

tad

1

Temperature Advection (K/s)

TH

th

1

Potential Temperature (K)

THE

the

1

Equivalent Potential Temperature (K)

PS

ps

1

Surface Pressure (Pa)

VOR

vor

1

Vorticity (/s)

MR

mr

1

Mixing Ratio (g/kg)

MRC

mrc

1

Moisture Convergence (g/kg/s)

DIV

div

1

Divergence (/s)

THA

tha

1

Potential Temperature Advection (kg/s)

MRA

mra

1

Moisture Advection (g/kg/s)

SPD

spd

1

Surface Wind Speed (m/s)

CSS

cssi

1

Colorado Severe Storm Index (none)

VIS

vis

1

Surface Visibility (m)

FWX

fwx

1

Fire Danger (none)

HI

hi

1

Heat Index (none)

TGD

tgd

1

Ground Temperature (K)

temp: LT1

HT

ht

21

Height (m)

T3

t3

21

Temperature (K)

accum: L1S

S01

s01

1

60 Minute Snow Accumulation (m)

STO

sto

1

Storm-Total Snow Accumulation (m)

R01

r01

1

60 Minute Liq Precip Accum (m)

RTO

rto

1

Storm-Total Liquid Precipitation Accumulation (m)

humid: LQ3

SH

sh

21

Specific Humidity (kg/kg)

humid: LH3

RH3

rh3

21

Relative Humidity (%)

RHL

rhl

21

Relative Humidity with resp to Liquid (%)

humid: LH4

TPW

tpw

1

Integrated Total Precipitable Water Vapor (m)

wind: LW3

U3

u3

21

u Component of Wind (m/s)

V3

v3

21

v Component of Wind (m/s)

OM

om

21

Wind Omega (Pa/s)

wind: LWM

SU

u

1

u Component of Surface wind (m/s)

SV

v

1

v Component of Surface wind (m/s)

cloud: LC3

LC3

lc3

42

Fractional Cloud Cover (levels 1-42) (0-1)

cloud: LCB

LCB

lcb

1

Cloud Base (m)

LCT

lct

1

Cloud Top (m)

CCE

cce

1

Cloud Ceiling (m)

cloud: LCV

LCV

cco

1

Cloud Cover (0-1)

CSC

csc

1

Cloud Analysis Implied Snow Cover (0-1)

CWT

cwt

1

Clear Sky Water Temperature (K)

S8A

s8a

1

IR Channel 4 (11.2µ) b-temp:averaged (K)

S3A

s3a

1

IR Channel 2 (3.9µ) b-temp:averaged (K)

ALB

alb

1

LAPS Derived Albedo (0-1)

soil: LM1

LSM

lsm

3

Soil Moisture (m/m)

soil: LM2

CIV

civ

1

Cumulative Infiltration Volume (m)

DWF

dwf

1

Depth To Wetting Front (m)

WX

wx

1

Wet/Dry Grid Point (none)

EVP

evp

1

Evaporation Data (m/s)

SC

sc

1

Snow Covered (0-1)

SM

sm

1

Snow Melt (m3/m3)

MWF

mwf

1

Wetting Front Soil Moisture Content (m3/m3)
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File and Directory Structure

Processed LAPS files are available in compressed (tarred and zipped) files, such as laps-3d.20030610.tar.gz and laps-2d.20011214.tar.gz.

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File Size

The size of the entire data set is 148.3 GB. Daily 2-D files are approximately 38 MB each, and daily 3-D files are approximately 170 MB each.

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Spatial Coverage and Resolution

LAPS data covers the CLPX Large Regional Study Area, shown in the following map. LAPS covers a 10-km horizontal grid.

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Temporal Coverage and Resolution

LAPS data were produced hourly from 1 September 2001 through 31 August 2003.

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Parameter or Variable

LAPS parameters are meteorological parameters, as shown in Table 1.

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Software and Tools

Software and Tools

The NetCDF package required for LAPS is available at https://github.com/Unidata/netCDF-Decoders. Version netcdf 3.3.1 or higher is required. For a list of tools for reading/viewing netCDF files, please see the NetCDF Resources at NSIDC: Software and Tools Web page.

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Data Acquisition and Processing

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References and Related Publications

Albers, S. C., 1995: The LAPS wind analysis. Wea. Forecasting, 10,342-52.

Albers S. C., J. A. McGinley, D. L. Birkenheuer, and J. R. Smart, 1996: The Local Analysis and Prediction System (LAPS): Analyses of clouds, precipitation, and temperature. Wea. Forecasting, 11, 273-287.

Birkenheuer, D., 1999: The effect of using digital satellite imagery in the LAPS moisture analysis. Wea. Forecasting, 14, 782-788.

McGinley, J. A., S. C. Albers, and P. A. Stamus, 1991: Validation of a composite convective index as defined by a real-time local analysis system. Wea. Forecasting, 6, 337-356.

RELATED DATA COLLECTIONS

Contacts and Acknowledgments

Glen E. Liston
Atmospheric Sciences 
S205 ATMOS. SCIENCE ANNEX
Colorado State University
Fort Collins, CO 80523

Document Information

DOCUMENT CREATION DATE

1 December 2004

No technical references available for this data set.

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