GCIP LSA-NW EAOP 2000 SNOTEL Daily Precip Data in QC format
1.0 General Description
The Natural Resources Conservation Service (NRCS) SNOwpack
TELemetry (SNOTEL) precip data in QC format is one of several precip
datasets provided in the GEWEX Continental-Scale International Project
(GCIP) Large Scale Area-North West (LSA-NW) Enhanced Annual Observing
Period (EAOP) 2000. This dataset contains data for the GCIP LSA-NW
EAOP-00 domain and time period (01 April 2000 through 31 March 2001).
The GCIP LSA-NW EAOP-00 domain is approximately 90W to 115W longitude
and 36N to 51N latitude. These data were not quality controlled by the
University Corporation for Atmospheric Research/Joint Ofice for Science
Support (UCAR/JOSS).
2.0 Detailed Data Description
NRCS/SNOTEL Algorithms
The following algorithms apply to the NRCS Snow Telemetry
(SNOTEL) Daily Precip Data in QC format.
Note that these DATA ARE PROVISIONAL AND SUBJECT TO REVISION.
The following parameter was converted to JOSS QCF format when it
existed in the raw data:
Prec - "Accumulated Precip Since", in inches x 100 was converted to
QC format incremental precipitation in mm. The accumlation period
was reset on Oct 1 of each year.
No other parameters were converted.
The algorithms used to produce NRCS/SNOTEL daily precip data
are not currently available. Information about these stations can be
found at the NRCS website at
2.1 Detailed Format Description
The GCIP LSA-NW EAOP-00 Daily Precip Data contains ten
metadata parameters and 38 data parameters and flags. The metadata
parameters describe the station location and time at which the
data were collected. The time of observation is reported both in
Universal Time Coordinated (UTC) Nominal and UTC actual time. Days begin
at UTC hour 0100 and end at UTC hour 0000 the following day. The data
parameters are valid for the reported times. Missing values are
reported as 9's in the data field. The table below details the data
parameters in each record. Several data parameters have an associated
Quality Control (QC) Flag Code. For a list of possible QC Flag values
see the Quality Control Section 3.0.
Parameters Units
---------- -----
Date of Observation UTC Nominal
Time of Observation UTC Nominal
Date of Observation UTC actual
Time of Observation UTC actual
Network Identifier Abbreviation of platform name
Station Identifier Network Dependent
Latitude Decimal degrees, South is
negative
Longitude Decimal degrees, West is
negative
Station Occurrence Unitless
Station Elevation Meters
Station Pressure, QC flag Hectopascals (mb)
Reported Sea Level Pressure, QC flag Hectopascals (mb)
Computed Sea Level Pressure, QC flag Hectopascals (mb)
Dry Bulb Temperature, QC flag Celsius
Dew Point, QC flag Celsius
Wind Speed, QC flag m/s
Wind Direction, QC flag Degrees
Total Precipitation, QC flag mm
Squall/Gust Indicator Code Value
Squall/Gust Value, QC flag m/s
Present Weather, QC flag Code Value
Visibility, QC flag Meters
Ceiling Height (first layer) Hundreds of feet
Ceiling Flag (first layer), QC flag Code Value
Cloud Amount (first layer), QC flag Code Value
Ceiling Height (second layer) Hundreds of feet
Ceiling Flag (second layer), QC flag Code Value
Cloud Amount (second layer), QC flag Code Value
Ceiling Height (third layer) Hundreds of feet
Ceiling Flag (third layer), QC flag Code Value
Cloud Amount (third layer), QC flag Code Value
The list of code values for the Present Weather is too large to reproduce
in this document. Refer to WMO, 1988 for a complete list of Present Weather
codes.
The code values for the Squall/Gust Indicator are:
Code Definition
---- ----------
blank No Squall or Gust
S Squall
G Gust
The code values for the Ceiling Flag Indicator are:
Code Definition
---- ----------
0 None
1 Thin
2 Clear below 12,000 feet
3 Estimated
4 Measured
5 Indefinite
6 Balloon
7 Aircraft
8 Measured/Variable
9 Clear below 6,000 feet (AUTOB)
10 Estimated / Variable
11 Indefinite / Variable
12 12-14 reserved
15 Missing
The code values for the Cloud Amount Indicator are:
Code Definition
---- ----------
0 0 ( or clear)
1 1 okta or less, but not zero or 1/10 or less, but not zero
2 2 oktas or 2/10-3/10
3 3 oktas or 4/10
4 4 oktas or 5/10
5 5 oktas or 6/10
6 6 oktas or 7/10-8/10
7 7 oktas or more, but no 8 oktas or 9/10 or more,
but not 10/10
8 8 oktas or 10/10 (or overcast)
9 Sky obscured by fog and/or other meteorological phenomena
10 Sky partially obscured by fog and/or other
meteorological phenomena
11 Scattered
12 Broken
13 13-14 Reserved
15 Cloud cover is indiscernible for reasons other than fog or
other meteorological phenomena, or observation is not made.
2.2 Data Remarks
3.0 Quality Control Processing
These data were not quality controlled by UCAR/JOSS. See Table 3-1
for a list of the possible quality control flags and their meanings.
Table 3-1 - Quality Control Flags
4.0 References
Bolton, D., 1980: The computation of equivalent potential temperature.,
Mon. Wea. Rev., 108, pp 1046-1053.
Wallace, J.M., P.V. Hobbs, 1977: Atmospheric Science, Academic Press,
467 pp.
World Meteorological Organization (WMO), 1988: Manual on Codes
Volume I, Part B - Binary Codes. WMO, Geneva, Switzerland.