This data set contains various vegetation parameters for several locations from Oklahoma North (ON) and Oklahoma South (OS).
SMEX03 Vegetation Data: Oklahoma, Version 1
This is the most recent version of these data.
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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].Detailed Data Description
This data set contains various vegetation parameters for several locations from Oklahoma North (ON) and Oklahoma South (OS).
Data are in tab-delimited ASCII text files.
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
|
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 |
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 |
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 |
|
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, 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 |
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 |
|
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 |
The total volume is approximately 97 KB.
Southernmost Latitude: 34.8º N
Northernmost Latitude: 35.9º N
Westernmost Longitude: 98.3º W
Easternmost Longitude: 97.6º W
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.
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 | |
Software and Tools
Data Acquisition and Processing
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
- Determine by manual collection the water content for a known number of plants
- Convert to a per plant basis
- Calculate the number of plants per square meter using the row and plant spacing
- Multiply the water content per plant by the number of plants per square meter to get water content per square meter
Non-Row Crops
- Determine by manual collection the water content for a 0.44 meter by 0.44 meter area
- Divide the water content by 0.1936 to get water content per square meter
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.
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 .
References and Related Publications
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
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