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Data Set ID:
NSIDC-0287

SMEX03 Regional Ground Soil Moisture Data: Alabama, Version 1

This data set comprises gravimetric soil moisture and soil bulk density data collected during the Soil Moisture Experiment 2003 (SMEX03), which was conducted during June and July of 2003 in northern Alabama and southern Tennessee, USA.

Geographic Coverage

Parameter(s):
  • Soils > Soil Bulk Density
  • Soils > Soil Moisture/Water Content
Spatial Coverage:
  • N: 35.14, S: 34.71, E: -85.82, W: -87.05

Spatial Resolution: Not Specified
Temporal Coverage:
  • 22 June 2003 to 2 July 2003
Temporal Resolution: Not specified
Data Format(s):
  • ASCII Text
Platform(s) FIELD SURVEYS, GROUND-BASED OBSERVATIONS
Sensor(s): SOIL SAMPLER
Version: V1
Data Contributor(s): Frank Archer, Charles Laymon
Data Citation

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.

Archer, F. and C. Laymon. 2006. SMEX03 Regional Ground Soil Moisture Data: Alabama, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: http://dx.doi.org/10.5067/IW5SNOPDGNOZ. [Date Accessed].

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Detailed Data Description

File Descriptions

Table 1 lists the files contained in this data set.

Table 1: Files Contained in this Data Set

File Name

Parameter

File Size

GSM_AL_v2.txt Ground Soil Moisture

54 KB

BD_AL_v2.txt Bulk Density

11 KB

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Format

Format

Data are provided as comma-delimited text files. Table 2 and Table 3 list the column headings in each data file, and give a description of the type of information found under each column heading.

Table 2: Column Headings and Description for the GSM_AL _v2.txt

Column Heading

Description

Date Date readings made
DOY Numerical day of the year
Site ID Alabama site number (1-59)
Latitude Latitude in decimal degrees
Longitude Longitude in decimal degrees
0-3 cm Can wt. (g) Weight (g) of can at the 0-3 cm depth
0-3 cm Wet wt. (g) Weight (g) of soil and can at the 0-3 cm depth prior to drying
0-3 cm Dry wt. (g) Weight (g) of soil and can at the 0-3 cm depth after drying
0-3 cm GSM (g/g) Gravimetric soil moisture (g/g) of sample at the 0-3 cm depth
3-6 cm Can wt. (g) Weight (g) of can at the 3-6 cm depth
3-6 cm Wet wt. (g) Weight (g) of soil and can at the 3-6 cm depth prior to drying
3-6 cm Dry wt. (g) Weight (g) of soil and can at the 3-6 cm depth after drying
3-6 cm GSM (g/g) Gravimetric soil moisture (g/g) for sample at the 3-6 cm depth
Data Quality Flag Data defined as missing and erroneous


 

Table 3: Column Headings and Description for the BD_AL_v2.txt

Column Heading

Description

Date Date readings made
DOY Numerical day of the year
Site ID Alabama site number (1-59)
Latitude Latitude in decimal degrees
Longitude Longitude in decimal degrees
0-3 cm Can wt. (g) Weight (g) of can at the 0-3 cm depth
0-3 cm Dry wt. (g) Weight (g) of soil and can at the 0-3 cm depth after drying
0-3 cm BD g/cm3 Bulk density (g/cm3) for sample at the 0-3 cm depth
3-6 cm Can wt. (g) Weight (g) of can at the 3-6 cm depth
3-6 cm Dry wt. (g) Weight (g) of soil and can at the 3-6 cm depth after drying
3-6 cm BD g/cm3 Bulk density (g/cm3) for sample at the 3-6 cm depth
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Volume

The entire data set is 65 KB.

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Spatial Coverage

Southernmost Latitude: 34.71° N
Northernmost Latitude: 35.14° N
Westernmost Longitude: 87.05° W
Easternmost Longitude: 85.82° W

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Temporal Coverage

Data were collected daily from 22 June 2003 to 2 July 2003.

Temporal Resolution

Cores were taken daily between 11:00 A.M. and 3:00 P.M. local time.

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Parameter or Variable

Parameter Description

Parameters in this data set include gravimetric soil moisture (g/g) and soil bulk density (g/cm).

Sample Data Record

Below is a partial sample record from the GSM_AL_v2.txt data file. The first four columns and last four columns of the data file are shown, and only the first four data records are shown.

Date

DOY

Site ID

Latitude

...

3-6 cm
Can wt.
(g)

3-6 cm
Wet wt.
(g)

3-6 cm
Dry wt.
(g)

3-6 cm
GSM
(g/g)

6/22/03

173

AL 01

35.111351

...

38.18

169.60

144.89

0.232

6/22/03

173

AL 02

35.125375

...

37.04

104.51

92.88

0.208

6/22/03

173

AL 03

35.050518

...

37.95

133.97

119.62

0.176

6/22/03

173

AL 04

35.042841

...

37.70

124.58

94.25

N/A

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Error Sources

Missing and erroneous data were identified based on field notes and post-experiment examination of output. Missing data are represented by the text -999.000, and suspect or questionable data values are noted in the last data column, titled Data Quality Flag.

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Software and Tools

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Data Acquisition and Processing

The 0-6 cm soil moisture profile was measured using a standard soil core sampler, the barrel of which was loaded with two metal cylinders 3 cm high and hammered into the soil. Following extraction of the sampler, the cylinder containing the soil sample was removed from the barrel. The core was sliced with a wide spatula at 3 cm intervals and each slice was analyzed separately. Refer to Figure 2. If soil moisture conditions were favorable and the soil was relatively free from gravel and plant residue, samples suitable for bulk density determination were obtained. The samples that were suitable for bulk density determination were noted in the field. For AMSR-E validation purposes, soil moisture was sampled each day between 11:00 a.m. and 3:00 p.m. local time.

Demonstraton of the Sliced Core Sampling Technique
Figure 1: Demonstration of the Sliced Core Sampling Technique


 

Processing Steps

The soil samples were weighed, dried, and then weighed again. Then the bulk density was computed using the following formula:

Bulk Density = dry soil mass extracted / soil volume extracted

And the gravimetric soil moisture was computed using the following formula:

Gravimetric soil moisture = (wet weight - dry weight) / dry weight

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References and Related Publications

Contacts and Acknowledgments

Frank Archer
Alabama A&M University, Global Hydrology and Climate Center
Huntsville, Alabama
USA

Charles Laymon
Universities Space Research Association, Global Hydrology and Climate Center
NASA Marshall Space Flight Center
Huntsville, Alabama
USA

Acknowledgments: 

We would like to thank Linda Cornett and Rashida Fambro at the Alabama A&M University, William Crosson and Ashutosh Limaye at the Marshall Space Flight Center, Huntsville, Alabama, and the many Alabama A&M students, faculty, and staff members who collected and processed the field data for this experiment.

Document Information

Document Creation Date

April 2006

No technical references available for this data set.
No FAQs or How Tos available for this data set.

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