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CLPX-Ground: ISA Corner Site Meteorological Data

Summary

This data set contains meteorological observations at 36 sites throughout the Small Regional Study Area (SRSA) of the NASA Cold Land Processes Field Experiment (CLPX) in Colorado, USA. Identical meteorological towers were located close to the four corners of nine 1 km x 1 km Intensive Study Areas (ISAs). At each site, measurements of air temperature, relative humidity, wind speed, and wind direction were made at 2 m (North Park) or 4 m (Fraser and Buffalo Pass) above ground level. Snow depth, soil moisture, and soil temperatures were also measured. Hourly meteorological observations were recorded between 20 September 2002 and 1 October 2003, although data were not necessarily continuous throughout this time period for all towers.

The NASA CLPX is a multi-sensor, multi-scale experiment that focuses on extending a local-scale understanding of water fluxes, storage, and transformations to regional and global scales. Within a framework of nested study areas in the central Rocky Mountains of the western United States, ranging from 1-ha to 160,000 km^2, intensive ground, airborne, and spaceborne observations are collected. Data collection focuses on two seasons: mid-winter, when conditions are generally frozen and dry; and early spring, a transitional period when both frozen and thawed, dry and wet conditions are widespread.

Citing These Data

We kindly request that you cite the use of this data set in a publication using the following citation example. For more information, see our Use and Copyright Web page.

Houser, P. and D. Kunera. 2005. CLPX-Ground: ISA Corner Site Meteorological Data. [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.

Overview Table

Category Description
Data format Comma-delimited ASCII
Spatial coverage and resolution Meso-cell Study Areas (MSAs) within the CLPX SRSA, northern Colorado
Temporal coverage and resolution 20 September 2002 to 1 October 2003, with 1-hour temporal resolution
File size 1 KB for header files to 1.3 MB for data files
Parameter(s) Wind speed, wind direction, air temperature, relative humidity, snow depth, soil moisture, soil temperature
Procedures for obtaining data Data are available via FTP. Access data

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. Document Information

1. Contacts and Acknowledgments

Investigator(s) Name and Title

Paul Houser
Center for Research on Environment and Water
4041 Powder Mill Road, Suite 302
Calverton, MD 20705-3106
USA

Technical Contact

NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449  USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org

2. Detailed Data Description

Thirty-six identical meteorological towers were located close to each corner of nine CLPX Intensive Study Areas (ISAs). At each site, measurements of air temperature, relative humidity, wind speed, and wind direction were made at either 2 m or 4 m above ground level. Snow depth, soil moisture, and soil temperatures were also measured. Meteorological observations were recorded at an hourly resolution between September 2002 and October 2003.

In addition to direct observations, parameters were generated within the logger program and as a result of post processing (year, month, day, hour and minute [HH:MM], and decimal day of year [Deci-DOY]). All time measurements were recorded in Greenwich Mean Time (GMT).

Each tower collected the following 22 specific parameters:

Year
Month
Day
HHMM [hour and minute]
Deci-DOY (decimal day of year)
Air Temperature [1-hr average] (°C)
Air Temperature [1-hr maximum] (°C)
Air Temperature [1-hr minimum] (°C)
Relative humidity [1-hr average] (%)
Relative humidity [1-hr maximum] (%)
Relative humidity [1-hr minimum] (%)
Wind speed [1-hr average] (ms-1)
Wind speed [1-hr maximum] (ms-1)
Wind speed [1-hr minimum] (ms-1)
Wind direction [1-hr average] (degrees)
Acoustic depth sounder (m)
Average hydraprobe temperature: 5 cm (°C)
Average hydraprobe soil water content: 5 cm (water fraction by volume, wfv)
Average hydraprobe temperature: 20 cm (°C)
Average hydraprobe soil water content: 20 cm (wfv)
Average hydraprobe temperature: 50 cm (°C)
Average hydraprobe soil water content: 50 cm (wfv)

For Deci-DOY:

12:00 midnight on day 100 is 100.0
6:00 a.m. on day 100 is 100.25
12:00 noon on day 100 is 100.5
6:00 p.m. on day 100 is 100.75

In addition, the data include photographs of the meteorological towers and surroundings. For each tower, there are six associated photographs: one of the tower, one looking down, and one looking from the tower in each compass direction.

Format

Meteorological data are presented in comma-delimited ASCII format. Each data file contains 22 parameters (columns), which are listed above, in consecutive 1-hour time intervals. Column header information for each data file is provided in a separate comma-delimited ASCII file (Headers.csv).

File Naming Convention

Data for each of the corner sites is contained in one file; the files are named as follows:

##$$_L1master_v1.0.csv

"##" refers to the two- or three-letter MSA, ISA code:

NM = North Park, Michigan River
NI = North Park, Illinois River
NP = North Park, Potter Creek
RB = Rabbit Ears, Buffalo Pass
RS = Rabbit Ears, Spring Creek
RW = Rabbit Ears, Walton Creek
FS = Fraser, St. Louis Creek
FF = Fraser, Fool Creek
FA = Fraser, Alpine

"$$" refers to the ISA corner:

NE = Northeast Corner
SE = Southeast Corner
NW = Northwest Corner
SW = Southwest Corner

Headers are not included in the first row of each data file. A separate file containing header information is provided, named Headers.csv.

A separate directory ("photos") contains photographs of the meteorlogical towers and the surrounding areas. There are six photographs associated with each tower: one of the tower, one looking down, and one looking from the tower in each compass direction. Photographs are named accordingly; for example, "FANE.JPG" is the photograph of the FANE site tower; "FANE-Down.JPG" is the downward-looking photograph; and "FANE-East.JPG" is the photograph looking eastward from the FANE site tower.

File Size

The uncompressed meteorological files range from 0.08 MB to 1.3 MB.

Spatial Coverage

Spatial coverage consists of the three MSAs within the SRSA (105° to 107.5° W, 39.5° to 41° N). One measurement tower was placed at, or close to, the corner of each ISA. Exact locations of each 2-m or 4-m high instrument tower are as follows:

Site ID UTM (Easting) UTM (Northing) Latitude Longitude Elevation (m)
FANE
426903 4411844 39.853 -105.855 3446
FANW
425903 4411844 39.853 -105.866 3429
FASE 426903 4410844 39.844 -105.854 3448
FASW 425903 4410844 39.844 -105.866 3449
FFNE 426488 4415259 39.884 -105.860 3118
FFNW 425482 4415254 39.884 -105.871 3074
FFSE 426488 4414259 39.875 -105.860 3305
FFSW 425480 4414277 39.875 -105.871 3255
FSNE 426262 4420309 39.930 -105.863 2724
FSNW 425331 4420250 39.929 -105.874 2742
FSSE 426210 4419285 39.920 -105.863 2712
FSSW 425258 4419312 39.921 -105.875 2776
NINE 394505 4506210 40.700 -106.249 2477
NINW 393504 4506210 40.700 -106.261 2474
NISE 394504 4505210 40.691 -106.249 2477
NISW 393504 4505210 40.691 -106.260 2495
NMNE 400494 4500540 40.650 -106.177 2559
NMNW 399494 4500540 40.650 -106.189 2544
NMSE 400494 4499540 40.639 -106.323 3564
NMSW 399537 4499555 40.641 -106.188 2561
NPNE 388657 4503210 40.672 -106.317 2478
NPNW 387653 4503210 40.672 -106.329 2485
NPSE 388695 4502181 40.663 -106.317 2482
NPSW 387566 4502188 40.663 -106.330 2485
RBNE 358076 4488891 40.537 -106.758 3256
RBNW 357076 4488891 40.538 -106.688 3170
RBSE 358076 4487891 40.530 -106.675 elevation data missing
RBSW 357076 4487891 40.529 -106.687 3097
RSNE 351588 4488451 40.534 -106.752 2747
RSNW 350588 4488451 40.533 -106.764 2720
RSSE 351588 4487451 40.525 -106.752 2845
RSSW 350588 4487451 40.524 -106.764 2752
RWNE 360645 4474079 40.406 -106.642 2981
RWNW 359645 4474079 40.405 -106.654 3006
RWSE 360645 4473079 40.397 -106.642 2929
RWSW 359645 4473079 40.396 -106.654 3007

Projection

Data are Universal Transverse Mercator (UTM) projection: Zone 13 North, based on the WGS84 datum.

Spatial Coverage Map

The following map shows the CLPX study area:

Temporal Coverage

Meteorological data were collected between September 2002 and October 2003; data are not continuous at all sites throughout this period.

Temporal Resolution

Measurements of all parameters were made every 10 seconds. For all parameters except snow depth, soil moisture content and soil temperature, measurements were averaged over every 1-hour period. For snow depth, soil moisture content, and soil temperature, no average was taken and instead a single sample measurement was recorded at the mid-point of each 1-hour period.

Parameter or Variable

Parameters presented in this data set are wind speed, wind direction, air temperature, relative humidity, snow depth, soil moisture, and soil temperature.

Parameter Minimum Value Maximum Value
Air temperature (°C) -50 50
Relative humidity (%) 0 105
Wind speed (ms-1) 0 50
Average hydraprobe temperature: 5 cm (°C) -50 50
Average hydraprobe soil water content: 5 cm (wfv) 0 0.7
Average hydraprobe temperature: 20 cm (°C) -50 50
Average hydraprobe soil water content: 20 cm (wfv) 0 0.7
Average hydraprobe temperature: 50 cm (°C) -50 50
Average hydraprobe soil water content: 50 cm (wfv) 0 0.7

Data that were considered suspect during manual filtering were left in Level 1 files even after they were identified as suspect. This was done when technicians recognized potential inconsistencies but were either unsure of the cause or were unable to verify their assumptions. Rather than alter the data set without definitive proof of faulty data, data were left for further interpretation and quality control by future investigators. Although the investigator has a high level of confidence in the products that are delivered in this data set, future investigators should implement their own quality control procedures.

Quality Assessment

The available data product has been processed to a Level 1 standard. This means that raw data (Level 0 data), which were downloaded on approximately a 6-month basis, have been concatenated into one continuous file per meteorological tower. Data have then been filtered twice for faulty values. The first filtering process was done manually to recognize instrument, wiring, or programming problems. The second filtering process was done computationally to remove blank values or any faulty values that fall outside of acceptable boundaries for each instrument (see table below for instrument list). Faulty data and missing data were replaced with a default value of 8999.

3. Data Access and Tools

Data Access

Data are available via FTP. Access data

Photos are available via FTP. Access photos

Related Data Collections

4. Data Acquisition and Processing

Sensor or Instrument Description

Variable Instrumentation
Air temperature Vaisala HMP45C Temperature and Relative Humidity Probe
Relative humidity Vaisala HMP45C Temperature and Relative Humidity Probe
Wind speed MetOne 034A Wind Monitor
Wind direction MetOne 034A Wind Monitor
Snow depth Judd Ultrasonic Depth Sensor
Average hydraprobe soil temperature Stevens Vitel Hydra Soil Moisture Probe
Average hydraprobe soil water content Stevens Vitel Hydra Soil Moisture Probe

Below are photographs of the wind monitor (top) and snow depth sensor (bottom):

Wind monitor

Snow depth sensor

Future investigators should use manufacturers' guidelines to calculate instrument error. No independent instrument calibration has been applied to these data.

A schematic illustrates the assembly of each meteorological tower. Observations were made along a cross-arm of the meteorological tower, at 2 m above the ground surface at the North Park MSA and 4 m above ground surface at all other sites. However, because of sloping ground beneath the cross-arms, these heights should only be considered as approximate values.

The data include six photographs associated with each tower: one of the tower, one looking down, and one looking from the tower in each compass direction. Photographs are named accordingly; for example, "FANE.JPG" is the photograph of the FANE site tower; "FANE-Down.JPG" is the downward-looking photograph; and "FANE-East.JPG" is the photograph looking eastward from the FANE site tower.

Measurement Location on Tower Parameters
Cross-arm (2 m to 4 m above ground surface) Wind speed, wind direction, snow depth, air temperature, relative humidity
At 5 cm, 20 cm, and 50 cm beneath ground surface Soil moisture content, soil temperature

In addition to direct observations, some parameters were generated within the logger program and as a result of post processing (year, month, day, HH:MM, and Deci-DOY). All time measurements were recorded in GMT.

5. Document Information

Acronyms and Abbreviations

The following acronyms and abbreviations are used in this document.

CLPX NASA Cold Land Processes Field Experiment
DOY Day of Year
IOP Intensive Observation Period
ISA Intensive Study Area
FTP File Transfer Protocol
GMT Greenwich Mean Time
LRSA Large Regional Study Area
MSA Meso-cell Study Area
SRSA Small Regional Study Area
WFV Water Fraction by Volume

Document Creation Date

27 June 2005

Document URL

http://nsidc.org/data/docs/daac/nsidc0173_clpx_ISA_corner_met/index.html