Mailing List

Print
Data Set ID:
NSIDC-0297

SMEX03 Vegetation Data: Oklahoma, Version 1

This data set contains various vegetation parameters for several locations from Oklahoma North (ON) and Oklahoma South (OS).

This is the most recent version of these data.

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):
  • VEGETATION > BIOMASS
  • VEGETATION > LEAF CHARACTERISTICS
  • VEGETATION > PLANT CHARACTERISTICS
  • VEGETATION > VEGETATION COVER
  • VEGETATION > VEGETATION INDEX
Data Format(s):
  • ASCII Text
Spatial Coverage:
N: 35.9, 
S: 34.8, 
E: -97.6, 
W: -98.3
Platform(s):GROUND-BASED OBSERVATIONS
Spatial Resolution:Not SpecifiedSensor(s):INFRARED THERMOMETERS, LICOR PLANT CANOPY ANALYZER, OPS, RADIOMETERS
Temporal Coverage:
  • 1 July 2003 to 18 July 2003
Version(s):V1
Temporal ResolutionNot specifiedMetadata XML:View Metadata Record
Data Contributor(s):Thomas Jackson, Lynn McKee

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.

Jackson, T. and L. McKee. 2007. SMEX03 Vegetation Data: Oklahoma, 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/A1E1EWIHPHAO. [Date Accessed].

Back to Top

Collapse All / Open All

Detailed Data Description

This data set contains various vegetation parameters for several locations from Oklahoma North (ON) and Oklahoma South (OS).

Format

Data are in tab-delimited ASCII text files.

Background color on
File and Directory Structure

The following files are contained in this data set.

File Name Description File Size
SMEX03_Raw_MSR_Overpass.txt Raw data file of MSR and LAI.
52 KB
SMEX03_Raw_Vegetation.txt Raw data file containing all data.
30 KB
SMEX03_Sum_MSR_Overpass.txt Summary data file of MSR and LAI data only.
5 KB
SMEX03_Sum_Vegetation.txt Summary data file containing all data.
10 KB
Table 1. Column Headings and Definitions SMEX03_Raw_MSR_Overpass.txt
Column Heading Description
FIELD Site location identification number, OS is the Oklahoma South region, ON is the Oklahoma North region, LW is Little Washita Watershed, SOY1 is a soybean field located in the Little Washita Watershed
CROP WW_Stubble is winter wheat that has been harvested.
DATE

Month/day/year

DOY

Day of year

TIME (CDT)

Time of sampling in Central Daylight Time (CDT)

SITE

Number of site within given field
Latitude WGS84

Decimal degrees
Longitude WGS84
UTM_Easting WGS84_Zone 14
UTM_Northing WGS84_Zone 14

WGS84, Zone 14, in meters
LAI Leaf Area Index

CropScan Multispectral Radiometer Reflectance Percent
485 nm AVG

Average of % reflectance at wavelength: 485 nm
485 nm STD Standard deviation of % reflectance at wavelength: 485 nm
560 nm AVG Average of % reflectance at wavelength: 560 nm
560 nm STD Standard deviation of % reflectance at wavelength: 560 nm
650 nm AVG Average of % reflectance at wavelength: 650 nm
650 nm STD Standard deviation of % reflectance at wavelength: 650 nm
660 nm AVG Average of % reflectance at wavelength: 660 nm
660 nm STD Standard deviation of % reflectance at wavelength: 660 nm
830 nm AVG Average of % reflectance at wavelength: 830 nm
830 nm STD Standard deviation of % reflectance at wavelength: 830 nm
850 nm AVG Average of % reflectance at wavelength: 850 nm
850 nm STD Standard deviation of % reflectance at wavelength: 850 nm
1240 nm AVG Average of % reflectance at wavelength: 1240 nm
1240 nm STD Standard deviation of % reflectance at wavelength: 1240 nm
1640 nm AVG Average of % reflectance at wavelength: 1640 nm
1640 nm STD Standard deviation of % reflectance at wavelength: 1640 nm
1650 nm AVG Average of % reflectance at wavelength: 1650 nm
1650 nm STD

Standard deviation of % reflectance at wavelength: 1650 nm
Table 2. Column Headings and Definitions for SMEX03_Raw_Vegetation.txt
Column Heading Description
FIELD Site location identification number, OS is the Oklahoma South region, ON is the Oklahoma North region, LW is Little Washita Watershed, SOY1 is a soybean field located in the Little Washita Watershed
CROP WW_Stubble is winter wheat that has been harvested. Plowed_WW is winter wheat that has been harvest and plowed.
DATE Month/day/year
DOY Day of year
TIME
(CDT)		 Time of sampling in Central Daylight Time (CDT)
SITE Number of site within field
Latitude WGS84 Decimal degrees, WGS84
Longitude WGS84 Decimal degrees, WGS84
UTM_Easting WGS84_Zone 14 WGS84_Zone 14, in meters
UTM_Northing 
WGS84_Zone 14		 WGS84, Zone 14, in meters
LAI Leaf Area Index
CropScan Multispectral Radiometer Reflectance Percent
485 nm 
AVG		 Average of % reflectance at wavelength: 485 nm
485 nm 
STD		 Standard deviation of % reflectance at wavelength: 485 nm
560 nm
AVG		 Average of % reflectance at wavelength: 560 nm
560 nm 
STD		 Standard deviation of % reflectance at wavelength: 560 nm
650 nm 
AVG		 Average of % reflectance at wavelength: 650 nm
650 nm 
STD		 Standard deviation of % reflectance at wavelength: 650 nm
660 nm 
AVG		 Average of % reflectance at wavelength: 660 nm
660 nm 
STD		 Standard deviation of % reflectance at wavelength: 660 nm
830 nm
AVG		 Average of % reflectance at wavelength: 830 nm
830 nm 
STD		 Standard deviation of % reflectance at wavelength: 830 nm
850 nm 
AVG		 Average of % reflectance at wavelength: 850 nm
850 nm 
STD		 Standard deviation of % reflectance at wavelength: 850 nm
1240 nm 
AVG		 Average of % reflectance at wavelength: 1240 nm
1240 nm 
STD		 Standard deviation of % reflectance at wavelength: 1240 nm
1640 nm 
AVG		 Average of % reflectance at wavelength: 1640 nm
1640 nm 
STD		 Standard deviation of % reflectance at wavelength: 1640 nm
1650 nm 
AVG		 Average of % reflectance at wavelength: 1650 nm
1650 nm 
STD

Standard deviation of % reflectance at wavelength: 1650 nm
Column Heading Description
Plant Height Plant height in cm
Plant Density Number of plants/m2
Total Wet Wt Total areal green biomass kg/m2
Leaves Wet Wt Areal green biomass kg/m2of leaves only
Stalks Wet Wt Areal green biomass kg/m2 of stalks only
Ears Wet Wt Areal green biomass kg/m2 of ears only
Total Dry Wt Total areal dry biomass kg/m2
Leaves Dry Wt Areal dry biomass kg/m2 of leaves only
Stalks Dry Wt Areal dry biomass kg/m2 of stalks only
Ears Dry Wt Areal dry biomass kg/m2 of ears only
Total Water Total areal water content kg/m2
Leaves Water Areal water content kg/m2of leaves only
Stalks Water Areal water content kg/m2 of stalks only
Ears Water Areal water content kg/m2of ears only
Notes Sampling notes
Table 3. Column Headings and Definitions for the file: SMEX03_Sum_MSR_Overpass.txt
Column Heading Description

FIELD

Site location identification number, LW is Little Washita Watershed, SOY1 is a soybean field located in the Little Washita Watershed

CROP

WW_Stubble is winter wheat that has been harvested.

DATE

month/day/year

DOY

Day of year
TIME
(CDT)

Time of sampling in Central Daylight Time (CDT)
Latitude
WGS84		 Decimal degrees, WGS84
Longitude 
WGS84

Decimal degrees, WGS84

UTM_Easting
WGS84_Zone14

WGS84, Zone 14, in meters
UTM_Northing
WGS84_Zone14

WGS84, Zone 14, in meters

LAI - AVG

Average of Leaf Area Index
LAI - STD Standard deviation of Leaf Area Index

Cropscan Multispectral Radiometer Reflectance Percent

485 nm – AVG

Average of % reflectance at wavelength: 485 nm

485 nm – STD

Standard deviation of % reflectance at wavelength: 485 nm

560 nm - AVG

Average of % reflectance at wavelength: 560 nm

560 nm - STD

Standard deviation of % reflectance at wavelength: 560 nm

650 nm - AVG

Average of % reflectance at wavelength: 650 nm

650 nm - STD

Standard deviation of % reflectance at wavelength: 650 nm

660 nm - AVG

Average of % reflectance at wavelength: 660 nm

660 nm - STD

Standard deviation of % reflectance at wavelength: 660 nm

830 nm - AVG

Average of % reflectance at wavelength: 830 nm

830 nm - STD

Standard deviation of % reflectance at wavelength: 830 nm

850 nm - AVG

Average of % reflectance at wavelength: 850 nm

850 nm - STD

Standard deviation of % reflectance at wavelength: 850 nm

1240 nm - AVG

Average of % reflectance at wavelength: 1240 nm

1240 nm - STD

Standard deviation of % reflectance at wavelength: 1240 nm

1640 nm - AVG

Average of % reflectance at wavelength: 1640 nm

1640 nm - STD

Standard deviation of % reflectance at wavelength: 1640 nm

1650 nm - AVG

Average of % reflectance at wavelength: 1650 nm

1650 nm - STD

Standard deviation of % reflectance at wavelength: 1650 nm
Table 4. Column Headings and Definitions for SMEX03_Sum_Vegetation.txt
Column Heading
Description

FIELD

Site location identification number, OS is the Oklahoma South region, ON is the Oklahoma North region, LW is Little Washita Watershed, SOY1 is a soybean field located in the Little Washita Watershed

CROP

WW_Stubble is winter wheat that has been harvested. Plowed_WW is winter wheat that has been harvest and plowed.

DATE

Month/day/year

DOY

Day of year

TIME

Time of sampling in CDT
Latitude
WGS84

Decimal degrees, WGS84
Longitude
WGS84		 Decimal degrees, WGS84
UTM_Easting
WGS84_Zone 14		 WGS84, Zone 14, in meters
UTM_Northing
WGS84_Zone 14		 WGS84, Zone 14, in meters
LAI – AVG Average of Leaf Area Index

LAI – STD

Standard deviation of Leaf Area Index

Cropscan Multispectral Radiometer Reflectance Percent

485 nm – AVG

Average of % reflectance at wavelength: 485 nm

485 nm – STD

Standard deviation of % reflectance at wavelength: 485 nm

560 nm – AVG

Average of % reflectance at wavelength: 560 nm

560 nm – STD

Standard deviation of % reflectance at wavelength: 560 nm

650 nm – AVG

Average of % reflectance at wavelength: 650 nm

650 nm – STD

Standard deviation of % reflectance at wavelength: 650 nm

660 nm – AVG

Average of % reflectance at wavelength: 660 nm

660 nm – STD

Standard deviation of % reflectance at wavelength: 660 nm

830 nm – AVG

Average of % reflectance at wavelength: 830 nm

830 nm – STD

Standard deviation of % reflectance at wavelength: 830 nm

850 nm – AVG

Average of % reflectance at wavelength: 850 nm

850 nm – STD

Standard deviation of % reflectance at wavelength: 850 nm

1240 nm – AVG

Average of % reflectance at wavelength: 1240 nm

1240 nm – STD

Standard deviation of % reflectance at wavelength: 1240 nm

1640 nm – AVG

Average of % reflectance at wavelength: 1640 nm

1640 nm – STD

Standard deviation of % reflectance at wavelength: 1640 nm

1650 nm – AVG

Average of % reflectance at wavelength: 1650 nm

1650 nm – STD

Standard deviation of % reflectance at wavelength: 1650 nm
Column Heading Description
Plant Height - AVG Average of plant height in cm
Plant Height - STD Standard deviation of plant height in cm
Plant Density - AVG Average – Plants/m2
Plant Density - STD Standard deviation – Plants/m2

Total Wet Wt – AVG

Average of total areal green biomass kg/m2

Total Wet Wt – STD

Standard deviation of total areal green biomass kg/m2

Leaves Wet Wt - AVG

 Average – areal green biomass kg/m2 of leaves only
Leaves Wet Wt -STD Standard deviation – areal green biomass kg/m2of leaves only

Stalks Wet Wt – AVG

Average – areal green biomass kg/m2 of stalks only

Stalks Wet Wt – STD

Standard deviation – areal dry biomass kg/m2 of stalks only

Ears Wet Wt – AVG

Average – areal green biomass kg/m2 of ears only

Ears Wet Wt – STD

Standard deviation – areal green biomass kg/m2 of ears only
Total Dry Wt - AVG Average of total areal green biomass kg/m2
Total Dry Wt - STD Standard deviation of total areal green biomass kg/m2

Leaves Dry Wt - AVG

Average – areal dry biomass kg/m2 of leaves only

Leaves Dry Wt – STD

Standard deviation – areal dry biomass kg/m2 of leaves only

Stalks Dry Wt – AVG

Average – areal dry biomass kg/m2 of stalks only

Stalks Dry Wt – STD

Standard deviation – areal dry biomass kg/m2 of stalks only

Ears Dry Wt – AVG

Average – areal dry biomass kg/m2 of ears only

Ears Dry Wt – STD

Standard deviation – areal dry biomass kg/m2 of ears only

Total Water - AVG

Average of total areal water content kg/m2

Total Water – STD

Standard deviation of total areal water content kg/m2

Leaves Water – AVG

Average – areal water content kg/m2 of leaves only

Leaves Water – STD

Standard deviation – areal water content kg/m2 of leaves only

Stalks Water – AVG

Average – areal water content kg/m2 of stalks only

Stalks Water – STD

Standard deviation – areal water content kg/m2 of stalks only

Ears Water - AVG

Average – areal water content kg/m2 of ears only

Ears Water - STD

Standard deviation – areal water content kg/m2 of ears only

Notes

 Sampling notes
Background color on
Volume

The total volume is approximately 97 KB.

Background color on
Spatial Coverage

Southernmost Latitude: 34.8º N 
Northernmost Latitude: 35.9º N 
Westernmost Longitude: 98.3º W 
Easternmost Longitude: 97.6º W

Background color on
Temporal Coverage

Data were collected daily from 1-18 July 2003

Temporal Resolution

Data were collected 1-3 times on multiple days at multiple sites throughout the project.

Background color on
Parameter or Variable

Parameter Description

Parameters in this data set are Leaf Area Index (LAI), Multispectral Radiometer Reflectance (MSR), plant height, plant density, areal wet biomass, areal dry biomass, and areal water content. The following table describes the units of measurement and sources of each parameter.

Parameter

Unit of Measurement

Sensor

Leaf Area Index (LAI)

 NA

LI-COR LAI-2000

Multispectral Radiometer Reflectance (MSR)

 %

CropScan MSR-16R

Plant height

 cm

manual data collection

Plant density

 plants/m2

manual data collection

Areal wet biomass

 kg/m2

manual data collection

Areal dry biomass

 kg/m2

manual data collection

Areal water content

 kg/m2

manual data collection

Sample Data Record

For each sample file of this data set shown below, the first four and last four columns are displayed. The value -99 is a fill value for missing data.

The following sample shows the first five rows from SMEX03_Raw_MSR_Overpass.txt.

 1640 nm 1650 nm
FIELD CROP DATE DOY
...
 AVG STD AVG STD
LW03 Pasture 7/01/2003 182
...
 32.16 2.93 29.22 3
LW32 Bare_Soil 7/02/2003 183
...
 32.72 1.19 39.31 1.71
LW31 Corn 7/02/2003 183
...
 25.9 2.74 10.02 0.92
Quarry Gypsum_Quarry 7/02/2003 183
...
 70.2 4.37 35.41 2.48
LAKE Lake 7/02/2003 183
...
 9.92 1.7 5.31 2.19

The following sample shows the first five rows from SMEX03_Raw_Vegetation.txt.

 Leaves Stalks Ears
DATE Water Water Water
FIELD CROP (m/dd/yyyy) DOY ... kg/m2 kg/m2 kg/m2 NOTES:
SOY1 Soybeans 7/03/2003 184 ... -99 -99 -99 Biomass samples taken 7/04/2003
SOY1 Soybeans 7/03/2003 184 ... -99 -99 -99 Biomass samples taken 7/04/2003
SOY1 Soybeans 7/03/2003 184 ... -99 -99 -99 Biomass samples taken 7/04/2003
LW33 Alfalfa 7/04/2003 185 ... -99 -99 -99
LW33 Alfalfa 7/04/2003 185 ... -99 -99 -99

The following sample shows the first five rows from SMEX03_Sum_MSR_Overpass.txt.

 1640 nm 1650 nm
FIELD CROP DATE DOY
...
 AVG STD AVG STD
LW03 Pasture 7/01/2003 182
...
 32.16 2.93 29.22 3
LW32 Bare_Soil 7/02/2003 183
...
 32.72 1.19 39.31 1.71
LW31 Corn 7/02/2003 183
...
 25.9 2.74 10.02 0.92
Quarry Gypsum_Quarry 7/02/2003 183
...
 70.2 4.37 35.41 2.48
LAKE Lake 7/02/2003 183
...
 9.92 1.7 5.31 2.19

The following sample shows the first five rows from SMEX03_Sum_Vegetation.txt.

Stalks Ears Ears
Water Water Water
DATE kg/m2 kg/m2 kg/m2
FIELD CROP (m/dd/yyyy) DOY
...
 STD AVG STD NOTES:
SOY1 Soybeans 7/03/2003 184
...
 -99 -99 -99 Biomass samples taken 7/04/2003
LW33 Alfalfa 7/04/2003 185
...
 -99 -99 -99
LW11 Pasture 7/04/2003 185
...
 -99 -99 -99
LW12 Pasture 7/05/2003 186
...
 -99 -99 -99
LW13 Pasture 7/05/2003 186
...
 -99 -99 -99  
 
Background color on

Software and Tools

Background color on

Data Acquisition and Processing

Theory of Measurements

The goal of vegetation sampling is to generate the vegetation products used to estimate surface soil moisture from passive microwave radiometers. Sampling was designed to coincide with satellite overpasses, such as LandSat Thematic Mapper (TM5) and Terra-MODIS, which can be used to estimate vegetation water content on the regional scale.

Vegetation Moisture

Samples were collected manually. In the laboratory they were weighed, dried at 60º C for 48 to 96 hours, and then weighed again.

Section Sampling

Sampling was performed on sites approximately a quarter section (0.8 km by 0.8 km) in size. The sampling was concentrated in the Little Washita watershed, but several locations from Oklahoma North (ON) and Oklahoma South (OS) were also sampled. Each Little Washita watershed site was sampled twice during the field campaign, Oklahoma North and South sites were only sampled once. Sampling consisted of recording vegetation height and plant density, collecting vegetation biomass samples, and taking reflectance and LAI measurements. Three locations in each of the sites were sampled, and every effort was made to have these three locations coincide in soil moisture sampling points. The sampling was conducted between 09:00 and 15:00 local time.

Transect Sampling

Several Little Washita watershed sites (representing the dominate types of vegetation) were characterized by transect sampling. Reflectance and LAI measurement were collected at each of the soil moisture sampling locations (14 total). A gypsum quarry and a lake were also sampled for calibration purposes. This was done three times, once to coincide with the each Landsat overpass.

Computing Areal Water Content

The following steps were used to compute areal water content.

Row Crops

  1. Determine by manual collection the water content for a known number of plants
  2. Convert to a per plant basis
  3. Calculate the number of plants per square meter using the row and plant spacing
  4. Multiply the water content per plant by the number of plants per square meter to get water content per square meter

Non-Row Crops

  1. Determine by manual collection the water content for a 0.44 meter by 0.44 meter area
  2. Divide the water content by 0.1936 to get water content per square meter
Background color on
Derivation Techniques and Algorithms

Errors and Limitations

Leaf Area Index

Direct-beam radiation reflected into the sensor from upper leaves in the canopy can be confused with open sky, causing LAI to be underestimated. Samplers were instructed to sample with the sun to their backs, but occasionally direct sunlight may enter the sensor. The data were examined for this and for evidence of variable sky conditions during the measurement sequence.

Multispectral Radiometer

The radiometer performs near simultaneous inputs of incident as well as reflected irradiation. This allows useful measurements of percent reflectance to be obtained during cloudy conditions with incident irradiance levels down to approximately 300 watts/m2. Measurements obtained with an incident irradiance level of less than 300 watts/m2 had to be discarded. One day it was too cloudy to take any multispectral radiometer measurements.

Background color on
Sensor or Instrument Description

Leaf Area Index Meter

Investigators used LiCor LAI-2000 plant canopy analyzers to measure LAI using an indirect noncontact method based on light transmittance through the canopy. The LAI-2000 calculates LAI from radiation measurements made with a fish-eye optical sensor (148 degree field-of-view). Measurements made above and below the canopy are used to determine canopy light interception at five angles. Measurements are made by positioning the optical sensor and pressing a button, which sends the data to the data logger. Multiple below-canopy readings are taken so that LAI calculations are based on a large sample of the foliage canopy. After collecting above-canopy and below-canopy measurements, the control data logger performs all calculations and the results are available for immediate inspection. For more information, visitwww.licor.com/env/Products/AreaMeters/index.jsp .

Multispectral Radiometer

Investigators used MSR-16R multispectral radiometers manufactured by CropScan to measure reflectance. The CropScan MSR is an inexpensive instrument that has up-and-down-looking detectors and the ability to measure sunlight at different wavelengths. The CropScan MSR systems consist of a radiometer, data logger controller (DLC) or A/D converter, terminal, telescoping support pole, connecting cables and operating software. The radiometer uses silicon or germanium photodiodes as light transducers. Matched sets of the transducers with filters to select wavelength bands are oriented in the radiometer housing to measure incident and reflected irradiation. In this experiment the wavelengths measured were 485, 560, 650, 660, 830, 850, 1240, 1640, and 1650 nm. These bands provide data for selected channels of the Landsat Thematic Mapper and MODIS instruments. Channels were chosen to provide Normalized Difference Vegetation Index (NDVI) as well as a variety of vegetation water content indices under consideration. For more information, visit www.cropscan.com/msr.html .

Background color on

References and Related Publications

Jackson, T. and L. McKee. 2007. SMEX03 Vegetation Data: Oklahoma. [indicate subset used]. Boulder, Colorado USA: NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: 10.5067/A1E1EWIHPHAO.

RELATED DATA COLLECTIONS

See related information on the NSIDC Soil Moisture Experiment (SMEX) Web site.

RELATED WEB SITES

Please visit the SMEX03 Web site for more information, and see the NSIDC SMEX Web site to access data.

Contacts and Acknowledgments

Investigator(s)

Thomas J. Jackson
USDA ARS Hydrology and Remote Sensing Lab
Beltsville, Maryland
USA

Lynn McKee
USDA ARS Hydrology and Remote Sensing Lab
Beltsville, Maryland
USA

Acknowledgments: 

Many graduate students and volunteers worked to collect the field data. We would like to thank the Soil Moisture Experiment 2003 Science Team and the Grazinglands Research Laboratory for their assistance.We would also like to thank NASA for their generous contributions to the study. This work was supported by the NASA Aqua AMSR, Terrestrial Hydrology, and Global Water Cycle Programs.

Document Information

DOCUMENT CREATION DATE

December 2006

DOCUMENT REVISION DATE

No technical references available for this data set.

How To

V0 Programmatic Data Access Guide
Data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) can be accessed directly from our HTTPS file system. We provide basic command line Wget and curl instructions for HTTPS file system downloads below. For questions about programmatic access to NSIDC... read more
Access complete Knowledge Base

Questions? Please contact:
NSIDC User Services
Phone: 1 303 492-6199
Email: nsidc@nsidc.org