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Sub-canopy Energetics at the CLPX Local Scale Observation Site (LSOS)

Summary

This data set consists of data from two pine sites at the Local Scale Observation Site (LSOS) of the Cold Land Processes Experiment (CLPX) in northern Colorado. The LSOS is a 100 x 100-m study site located within the Fraser Intensive Study Area (ISA). The study area has flat topography with both a dense pine forest and an open pine forest. Parameters measured include sub-canopy incoming solar and longwave radiation, air temperature, relative humidity, wind speed,snow depth, and snow wetness. Data were collected during February and March 2002 and 2003.

The NASA Cold Land Processes Experiment (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 km2, 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:

Hardy, J., G. Koenig, D. Cline, K. Elder, R. Davis. 2002. Sub-canopy energetics at the CLPX Local Scale Observation Site (LSOS). Boulder, CO: National Snow and Ice Data Center. Digital Media.

Overview Table

Category Description
data format Microsoft Excel Spreadsheet
spatial coverage 100 x 100m in northern Colorado, US
temporal coverage and resolution Midwinter and spring seasons, 2002
file size 20 to 4,500 KB
parameter(s) Sub-canopy incoming solar radiation, longwave radiation, air temperature, relative humidity and wind speed. Snow wetness and snow depth surveys.

Table of Contents

1.Contacts
2. Detailed Data Description
3.Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts:

Investigator(s) Name and Title:

Janet P. Hardy
CLPX - LSOSCoordinator
ERDC-CRREL
72 Lyme Road
Hanover, NH 03744-1290

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::

Format:

Data are stored in Microsoft Excel files.

Missing data are identified by "-999".

1. Sub-canopy meteorological data:

Meteorological data are available in Excel spreadsheet files, with a file extension of .xls. There are three met files (IOP1, March 2002, and IOP2) for the LSOS, with filenames of met_iop1lsos.xls and met_200203lsos.xls, and met_iop2lsos.xls, respectively.

Files named met_iop1lsos.xls and met_iop2lsos.xls contain three worksheets each, labeled Dense Pine, Open Pine, Tree 21. The met_iop files contain the following fields in the Dense Pineworksheet:

	Column 1: YEAR, 4 digit year
	Column 2: DOY - Day of Year
	Column 3: TIME - hhmm
	Column 4: WS - Mean Horizontal Wind Speed, averaged over previous time step. 
			Units in meters per second.
	Column 5: WD - Mean Wind Direction, averaged over previous time step. 
			Units in degrees.
	Column 6: PSP1.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 7: PSP2.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 8: PSP3.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 9: PSP4.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 10: PSP5.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 11: PSP6.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 12: PSP7.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 13: PSP8.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 14: PSP9.adj - Mean incoming solar radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 15: PSP10.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 16: PIR2.adj - Mean incoming longwave radiation averaged over previous time 
				step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 17: PIR3.adj - Mean incoming longwave radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 18: Mean Air Temperature averaged over previous time step. Units in degrees Celcius. 
	Column 19: Mean Relative Humidity averaged over previous time step. Units are percent.
	Column 20: Battery Voltage sampled at time step. Units are voltage.

The met_iop files contain the following fields in the Open Pine worksheet:

	Column 1: YEAR, 4 digit year
	Column 2: DOY - Day of Year
	Column 3: TIME - hhmm
	Column 4: PSP1.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 5: PSP2.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 6: PSP3.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 7: PSP4.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 8: PSP5.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 9: PSP6.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 10: PSP7.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 11: PSP8.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 12: PSP9.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 13: PSP10.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 14: PIR1.adj - Mean incoming longwave radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 15: PIR2.adj - Mean incoming longwave radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 16: Battery Voltage sampled at time step. Units are voltage.

The met_iop files contain the following fields in the Tree 21 worksheet:

	Column 1: YEAR, 4 digit year
	Column 2: DOY - Day of Year
	Column 3: TIME - hhm
	Column 4: Battery Voltage sampled at time step. Units are voltage.
	Column 5: Matrix0 - Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 6: Matrix1- Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 7: Matrix2- Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 8: Matrix3- Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 9: Matrix4- Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 10: Matrix5- Mean incoming solar radiation averaged over previous
			time step. Units are Watts per meter squared.
	Column 11: Matrix6- Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 12: Matrix7- Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 13: Matrix8- Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 14: Matrix9 Mean incoming solar radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 15: K&Z 1 - Mean incoming longwave radiation averaged over previous 
			time step. Units are Watts per meter squared.
	Column 16: K&Z 2 - Mean incoming longwave radiation averaged over 
			previous time step. Units are Watts per meter squared.

The file named met_200203lsos.xls contains one worksheet labeled Dense Pine. The data provided in column 6 (PSP 1.adj) are NOT quality controlled in terms of deleting (or flagging) data when the pyranometer is snow-covered as no-one was on site during this period to keep the pyranometers clear of snow.

	Column 1: YEAR, 4-digit year
	Column 2: DOY - Day of Year
	Column 3: TIME - hhmm
	Column 4: WS - Mean Horizontal Wind Speed, averaged over previous 
			time step. Units in meters per second.
	Column 5: WD - Mean Wind Direction, averaged over previous time step. Units in degrees.
	Column 6: PSP1.adj - Mean incoming solar radiation averaged over previous 
				time step and adjusted for recalibrated radiometer in July 2002. 
				Units are Watts per meter squared.
	Column 7: Mean Air Temperature averaged over previous time step. Units in degrees Celcius. 
	Column 8: Mean Relative Humidity averaged over previous time step. Units are percent.
	Column 9: Battery Voltage sampled at time step. Units are voltage.

2. Snow Depth Survey Data:

Snow depth data are available in Microsoft Excel files, with a file extension of .xls. There are three snow survey files for IOP1 and IOP2 with filenames depth__DATElsos.xls, where:

DATE = date in YYYY_MM_DD
.xls = Excel extension

Each file has three "worksheets" labeled: Dense Pine, Open Pine, and Snow Pits.

All three surveys were conducted by walking along established paths in the same order each time. In the dense pine site, the snow survey begins at the met tower and radiates out to each radiometer in approximately 1-m intervals. After measuring snow depths along the path to each radiometer, then we measured depth along a west to east traverse and a north to south traverse. In the open pine site we measured snow depths radial from the central datalogger box, along the paths to each radiometer. Finally, measures of snow depth were made along the path toward Tree 21. At each of the six snow pit locations a measure of at least ten snow depths were made during each survey.

Snow Depth Transect Files

Snow depth transect files contain measures of snow depth in centimeters with column headings identifying the path where measurements were made.

3. Snow Wetness Data:

Snow wetness data are available in a Microsoft Excel files, with a file extension of .xls. There is one snow wetness file, with separate workbooks for IOP1 and IOP2, with a filename of wetness_2002lsos.xls

Measurements of snow wetness were made using a Denoth snow moisture meter at each snow pit and calculating the percent snow wetness using the provided equation.

Snow Wetness File:

	Column A: Location of measurement (pit #). Letter next to pit number refers to the 
			date the snow pit was measured and corresponds to submitted snow pit data.
	Column B: Date in MM/DD/YYYY format
	Column C: Time of measurement in 2400-hour time.
	Column D: Depth the moisture sensing plate was inserted into the snow pit wall. 
			Depth in centimeters. The Denoth moisture meter senses snow moisture 3-cm 
			above and below sensor plate so a measurement at a depth of 10 cm provides 
			information on the snow moisture between 7-13 cm.
	Column E: Measured snow density in grams per cubic centimeter.
	Column F: Snow wetness as measured and calculated from the Denoth snow wetness 
			meter. Snow wetness is in percent.

Spatial Coverage:

Schematic diagram of the nested study areas for the CPLX
Study area map
Location of MSAs

The LSOS study site is a single, 1-ha study site located within the Fraser ISA, near the Fraser Experimental Forest Headquarters Facility. At this 100-m x 100-m site, intensive ground observations of snow, soil, and vegetation are made in conjunction with stationary, ground-based microwave remote sensing (active and passive) and micrometeorological observations. The site consists of two open meadows separated by a stand of short trees. Ground-based remote sensors will have an opportunity to view both a homogeneous area of open snow cover, and a homogenous stand of forest cover. At this scale, where spatial variability is relatively low, microwave remote sensing data, radiative-transfer models, detailed physical models of energy and mass balance of snow and the underlying soil, and ground observations can be most easily related to each other. Here, physical models and remote sensing retrieval algorithms can be evaluated with little ambiguity, and confidence levels can be established at the scale of our current understanding of important physical processes.

Temporal Coverage:

The experiment is being conducted between the Fall of 2001 and the Spring of 2003. Two intensive observation periods (IOPs) will be conducted each year: one during a dry period (February) and one during a wet period (March). The IOPs will be conducted on the same day-of-year (DOY) schedule each year.

IOP1 took place between February 19 and February 24, 2002.

MSA Scheduled Observation Period Actual Observation Period
Fraser 19-20 February 2002 Snow depth data collected 19-20 Feb. Snow pit data collected 20 Feb
North Park 21-22 February 2002 Snow depth and snow pit data collected 21 Feb. Additional snow pit data across the MSA (coincident with the Gamma overflights) were collected 22 Feb.
Rabbit Ears 23-24 February 2002 Snow depth data collected 23 Feb. Snow pit data collected 24 Feb.

IOP2 took place 25 March through 30 March 2002.

MSA Scheduled Observation Period Actual Observation Period
Fraser 25-26 March 2002 Snow depth data collected 25-26 March. Snow pit data collected 26 March
North Park 27-28 March 2002 Snow depth and snow pit data collected 27 March. Additional snow pit data across the MSA were collected 28 March
Rabbit Ears 29-30 March 2002 Snow depth data collected 29 March. Snow pit data collected 30 March.

Parameter or Variable:

Parameter Description:

Measurements at the LSOS include daily in-situ sampling of snow, soil, and vegetation characteristics at several locations within a fenced area. Snow and soil measurements include snow and soil pits, snow depth probing, and snow/soil interface temperature probing. The stem and canopy temperature, and xylem flux of several trees within the area is also monitored. Two micrometeorological towers, one located in the open snow area and the other in the forested area, monitor ambient conditions and provide forcing data sets for 1-D snow/soil models. These measurements, together with the ground-based remote sensing, will provide the framework for evaluating and improving microwave radiative transfer models and coupling them to land surface models.

For a complete description of parameters and measurements, please refer to the Measurements section of the CLPX Plan at http://www.nohrsc.nws.gov/~cline/clp/field_exp/clpx_plan/chapters/CLPX_plan_chap4.htm

Data Access and Tools:

Data Access:

Data are available via FTP to CLPX investigators. Users must register with and be approved by the Chair of the Cold Land Processes Working Group before receiving data. After one year, data will be available to users beyond CLPX investigators.

4. Data Acquisition and Processing:

For complete information about data acquisition and processing, please see the Cold Land Processes Field Experiment (CLPX) Plan Web Site.

5. References and Related Publications:

Please see the References section of the CLPX Plan.

6. Document Information:

Document Creation Date:

2002-11-15

Document Revision Date: