USCRN Standardized Soil Moisture Drought Index
UPDATED: 2021-08-27
README CONTENTS:
1. GENERAL INFORMATION
2. DIRECTORY / FILE ORGANIZATION
3. DATA VERSION / STATUS UPDATES
4. DATA FIELDS / FORMATS / IMPORTANT NOTES
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1. GENERAL INFORMATION
NCEI provides access to daily data from the U.S. Climate Reference Network
via anonymous ftp at:
ftp://ftp.ncei.noaa.gov/pub/data/uscrn/products/droughtindex01
and an identical web interface at:
http://www.ncei.noaa.gov/pub/data/uscrn/products/droughtindex01
Before using these data, be sure to review this document carefully, as well
as any announcements within the main (droughtindex01) directory.
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2. DATA VERSION / STATUS UPDATES
Status and Version Information for U.S. Climate Reference Network
Drought Index Dataset.
This is the initial Version 1.0.
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3. DIRECTORY / FILE ORGANIZATION
The directory contains a single comma delimited text file for each
USCRN station that monitors soil moisture conditions. Files list that
station's daily data for its soil moisture period of record.
These are named according to the following convention:
CRNDI01TT-${name}.csv
CRNDI01 = filename prefix to denote CRN DroughtIndex01 data
TT = 2-character file format number (currently 01)
${name} = station name (state location vector) (e.g. AZ_Tucson_11_W)
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4. DATA FIELDS / FORMATS
Each station file contains comma delimited fields with a single set of
daily data per line. A summary table of the fields and a detailed listing of
field definitions/column formats are shown below.
Please be sure to refer to the "Important Notes" section below for essential
information.
All daily data are calculated over the station's previous 7-days, ending at 12:00 UTC.
Field# Name Units
---------------------------------------------
1 WBANNO XXXXX
2 USDM_WEEK YYYYMMDD
3 LONGITUDE Decimal_degrees
4 LATITUDE Decimal_degrees
5 SMVWC_5_CM_MEAN m^3/m^3
6 SMANOM_5_CM_MEAN Standardized Units
7 SMPERC_5_CM_30COUNTS fraction
8 SMPERC_5_CM_70COUNTS fraction
9 SMVWC_10_CM_MEAN m^3/m^3
10 SMANOM_10_CM_MEAN Standardized Units
11 SMPERC_10_CM_30COUNTS fraction
12 SMPERC_10_CM_70COUNTS fraction
13 SMVWC_20_CM_MEAN m^3/m^3
14 SMANOM_20_CM_MEAN Standardized Units
15 SMPERC_20_CM_30COUNTS fraction
16 SMPERC_20_CM_70COUNTS fraction
17 SMVWC_50_CM_MEAN m^3/m^3
18 SMANOM_50_CM_MEAN Standardized Units
19 SMPERC_50_CM_30COUNTS fraction
20 SMPERC_50_CM_70COUNTS fraction
21 SMVWC_100_CM_MEAN m^3/m^3
22 SMANOM_100_CM_MEAN Standardized Units
23 SMPERC_100_CM_30COUNTS fraction
24 SMPERC_100_CM_70COUNTS fraction
25 SMVWC_TOP_CM_MEAN m^3/m^3
26 SMANOM_TOP_CM_MEAN Standardized Units
27 SMPERC_TOP_CM_30COUNTS fraction
28 SMPERC_TOP_CM_70COUNTS fraction
29 SMVWC_COLUMN_CM_MEAN m^3/m^3
30 SMANOM_COLUMN_CM_MEAN Standardized Units
31 SMPERC_COLUMN_CM_30COUNTS fraction
32 SMPERC_COLUMN_CM_70COUNTS fraction
1 WBANNO
The station WBAN number.
2 USDM_WEEK
The week ending on this day at 12:00 (UTC) that hourly observations
are aggregated over.
3 LONGITUDE
Station longitude, using WGS-84.
4 LATITUDE
Station latitude, using WGS-84.
5 SMVWC_5_CM_MEAN
The weekly average of hourly 5 cm soil moisture conditions.
6 SMANOM_5_CM_MEAN
The weekly average of hourly 5 cm standardized soil moisture anomalies.
7 SMPERC_5_CM_30COUNTS
The fraction of weekly hours 5 cm soil moisture percentiles were
less than or equal to the 30th percentile.
8 SMPERC_5_CM_70COUNTS
The fraction of weekly hours 5 cm soil moisture percentiles were
greater than or equal to the 70th percentile.
9 SMVWC_10_CM_MEAN
The weekly average of hourly 10 cm soil moisture conditions.
10 SMANOM_10_CM_MEAN
The weekly average of hourly 10 cm standardized soil moisture anomalies.
11 SMPERC_10_CM_30COUNTS
The fraction of weekly hours 10 cm soil moisture percentiles were
less than or equal to the 30th percentile.
12 SMPERC_10_CM_70COUNTS
The fraction of weekly hours 10 cm soil moisture percentiles were
greater than or equal to the 70th percentile.
13 SMVWC_20_CM_MEAN
The weekly average of hourly 20 cm soil moisture conditions.
14 SMANOM_20_CM_MEAN
The weekly average of hourly 20 cm standardized soil moisture anomalies.
15 SMPERC_20_CM_30COUNTS
The fraction of weekly hours 20 cm soil moisture percentiles were
less than or equal to the 30th percentile.
16 SMPERC_20_CM_70COUNTS
The fraction of weekly hours 20 cm soil moisture percentiles were
greater than or equal to the 70th percentile.
17 SMVWC_50_CM_MEAN
The weekly average of hourly 50 cm soil moisture conditions.
18 SMANOM_50_CM_MEAN
The weekly average of hourly 50 cm standardized soil moisture anomalies.
19 SMPERC_50_CM_30COUNTS
The fraction of weekly hours 50 cm soil moisture percentiles were
less than or equal to the 30th percentile.
20 SMPERC_50_CM_70COUNTS
The fraction of weekly hours 50 cm soil moisture percentiles were
greater than or equal to the 70th percentile.
21 SMVWC_100_CM_MEAN
The weekly average of hourly 100 cm soil moisture conditions.
22 SMANOM_100_CM_MEAN
The weekly average of hourly 100 cm standardized soil moisture anomalies.
23 SMPERC_100_CM_30COUNTS
The fraction of weekly hours 100 cm soil moisture percentiles were
less than or equal to the 30th percentile.
24 SMPERC_100_CM_70COUNTS
The fraction of weekly hours 100 cm soil moisture percentiles were
greater than or equal to the 70th percentile.
25 SMVWC_TOP_CM_MEAN
The weekly average of hourly Top (i.e. 5 & 10 cm) soil moisture conditions.
See note A.
26 SMANOM_TOP_CM_MEAN
The weekly average of hourly Top (i.e. 5 & 10 cm) standardized soil
moisture anomalies. See note A.
27 SMPERC_TOP_CM_30COUNTS
The fraction of weekly hours Top (i.e. 5 & 10 cm) soil moisture percentiles
were less than or equal to the 30th percentile. See note A.
28 SMPERC_TOP_CM_70COUNTS
The fraction of weekly hours Top (i.e. 5 & 10 cm) soil moisture percentiles
were greater than or equal to the 70th percentile. See note A.
29 SMVWC_COLUMN_CM_MEAN
The weekly average of hourly Column (i.e. all available depths) soil
moisture conditions. See note B.
30 SMANOM_COLUMN_CM_MEAN
The weekly average of hourly Column (i.e. all available depths) standardized
soil moisture anomalies. See note B.
31 SMPERC_COLUMN_CM_30COUNTS
The fraction of weekly hours Column (i.e. all available depths) soil
moisture percentiles were less than or equal to the 30th percentile.
See note B.
32 SMPERC_COLUMN_CM_70COUNTS
The fraction of weekly hours Column (i.e. all available depths) soil
moisture percentiles were greater than or equal to the 70th percentile.
See note B.
IMPORTANT NOTES:
A. The Top layer aggregate comprises of the 5 and 10 cm layers,
which were first average together and then standardized as
described in Leeper et al. (2019).
B. The Column layer aggregate comprises of all station depths (5 through
100 cm), which were first average together and then standardized
as described in Leeper et al. (2019). Note that not all USCRN
stations monitor soil moisture conditions below 10 cm. For these
stations, the column layer aggregate is set to missing.
Leeper, R. D., J. E. Bell, and M. A. Palecki, 2019: A Description and
Evaluation of U.S. Climate Reference Network Standardized Soil Moisture
Dataset. Journal of Applied Meteorology and Climatology, 58, 1417–1428.
http://dx.doi.org/10.1175/JAMC-D-18-0269.1