This dataset contains five-minute resolution surface meteorological data in University Corporation for Atmospheric Research/Joint Office for Science Support (UCAR/JOSS) Quality Control (QC) format from stations within the following networks:
Data for the International H2O Project 2002 (IHOP 2002) domain (32N to 42N latitude and 90W to 105W longitude) and time period (13 May 2002 through 25 June 2002) are contained within this dataset. This IHOP 2002 Five Minute Surface Composite dataset contains data from 261 stations.
Section 2.0 contains a detailed description of the
instrumentation, siting, and algorithms used by the source network to collect
the data. Section 2.1 contains a detailed
description of the format of the composite dataset. See
Section 2.2 for information on data processing, and
Section 3.0 below for the quality control processing performed by UCAR/JOSS
on this dataset. Section 4.0 contains references.
The Oklahoma Mesonet is a permanent mesoscale observing network. The
Mesonet consists of 115 stations, including at least one station in each of
Oklahoma's 77 counties. The average station spacing is 32 km.
Instrumentation
Algorithms
The following parameters are included in this IHOP 2002 Five Minute
Surface Composite. These parameters were measured at every site within the
Oklahoma Mesonet.
All reports are averages of three to thirty-second samples over the
preceding five minutes, except rainfall, which is an accumulation over the
previous five minutes.
Site Characteristics
Mesonet sites are predominantly located in rural areas, as free from
anthropogenic influences as possible (Shafer et al,
1993). A Site Standards
Committee developed a set of recommendations for site characteristics and
measurements. These recommendations were followed as closely as possible to
assure a consistency in the data reported from the field sites.
Instrumentation on the Mesonet was selected to conform as closely to WMO
standards as possible. Wind speed and direction are measured at a height of
10 m and air temperature and relative humidity are measured at 1.5 m for
consistency with existing NOAA cooperative observations and airport
stations. The measurements are taken over natural vegetation. The tower
stands near the center of a 10 m by 10 m plot of land, surrounded by a
cattle-panel fence, 1.3 m high, to secure the area from animals and nearby
human activity. Each site can be viewed on the worldwide web at the
following URL:
http://okmesonet.ocs.ou.edu. Two of the sites (Hobart and McAlester)
are co-located with ASOS instrumented towers so that data can be compared
between the two networks. Eleven additional sites are located within two km
of an NWS Cooperative Observer site. Two towers are installed at the Norman
site. One is operational while the other provides an opportunity to compare
instrumentation and test network upgrades without affecting the operational
sites.
Information on the mesonet, site information and photographs, and
a list of mesonet-related publications can be found on the
Oklahoma Mesonet web site
(Oklahoma Mesonet, 2003).
For information on, and to access, data and parameters not included in
this IHOP 5-minute surface composite, see the complete
IHOP_2002
Oklahoma Mesonet Meteorological Data (5-min) dataset in Oklahoma
Climate Survey (OCS) Format.
For information on the calculation of parameters derived by UCAR/JOSS
from the raw parameters available, see
Section 2.2.
The Integrated Surface Flux Facility (ISFF) is designed to study
exchange processes between the atmosphere and Earth's surface. This
includes the direct measurement of fluxes of momentum, sensible and latent
heat, trace gases, and radiation as well as standard atmospheric and
surface variables. Only surface variables are included in this IHOP
5-minute surface composite. There are 9 ISFF stations included in this
IHOP 2002 Five Minute Surface Composite.
Instrumentation
Measurements from the following instrumentation are included in this
IHOP 5-minute surface composite.
Wind speed and direction were calculated from U and V wind components.
Algorithms and Sensor Notes
Following are notes on the deployment, operation, and post-project
processing of data from each of the sensors. All deployment, operation,
and post-project processing described in this section were performed by
NCAR/ATD/ISFF. For information on the calculation of parameters derived by
UCAR/JOSS from the raw parameters available, see
Section 2.2. See Section 3.0 for the
quality control processing performed by UCAR/JOSS on the composite dataset
which contains this data.
Hygrothermometers
The Vaisala 50Y Humitters were calibrated in the NCAR Sensor Calibration
Laboratory prior to the IHOP field program. The 50Y temperature sensors
were calibrated over the range 0-45 C, and the relative humidity
sensors were calibrated over the range 10-90 %RH at 15, 25, and 35 C.
The calibration coefficients for temperature and relative humidity were
entered into the EPROMs of the individual NCAR hygrothermometers, and the
hygrothermometer microprocessors applied the coefficients to the 50Y output
to produce the calibrated temperature and humidity data that was archived
during the field project.
Following the field program, a second calibration data set was collected
with each 50Y, and the hygrothermometer outputs using the pre-project
calibration coefficients were compared to the laboratory standards.
In general the 50Y temperatures agreed with the laboratory standard within
�0.05 degrees, the exception being s/n 001 deployed at site 4 and having
an apparent offset on the order of -0.1 degrees. The 50Y relative
humidities agreed with the laboratory standards within �2 %RH, with the
exception of s/n 003-005 deployed at sites 7, 3, and 2 and having maximum
differences of 2.5-4 %RH.
Barometers
Barometer data are missing at station 8 for two extended periods, May 10
15:00 - May 15 17:15 CDT and May 25 02:00-10:35 CDT. In order to calculate
air density during those two periods, the atmospheric pressure at station 8
have been estimated with one of the following three formulas, depending on
the availability of pressure data from sites 7 and 9:
P8 = (P7 + P9)/2 - 1.72 mb
P8 = P7 - 5.26 mb
P8 = P9 + 1.82 mb
The pressure offsets in each of the preceding formulas was calculated from
IHOP data when it was available from all of the required barometers. A
comparison of the measured and estimated values of P8 finds that the errors
in the estimated values are generally considerably less than 1 mb. The mean
absolute error of the first formula is 0.1 mb, while those of the second
and third formulas are 0.2 mb.
Data edited when PAM mast in lowered position
It was occasionally necessary to lower the mast on the ISFF remote
stations, in order to service sensors mounted on the mast. During periods
when the mast was in a lowered position, data from the hygrothermometer,
barometer, and sonic anemometer have been eliminated from the QC data set
provided.
Rain gauge
False tips have been removed (replaced with 0) from the rain gauge data
to the extent possible. These include both false tips generated during
station service visits, as well as isolated tips that occur during
apparently clear sky situations.
The intent was to err on the side of possibly including a false tip
rather than deleting valid data. One apparent cause of the `clear sky'
false tips is mice living in the rain gauge. Mouse nests and/or mice were
found in the gauges at sites 1, 4, 5, 6, 8, and 9. No evidence of mice was
found at sites 3 and 7. No `clear sky' tips were detected at sites 2 and 3.
Sonic anemometers
The sonic anemometers were mounted with their booms extending to the
east of the PAM mast. It was planned to install the sonic anemometers at a
height z determined by the geometry and path length of the sonic array and
by the height of the vegetation, z = zs + D , where
However, in some cases it was not possible to mount the sonic boom at
exactly the planned height because it occurred at the same height as a
joint in the PAM mast. The actual heights, above ground level, were
These heights did not change during IHOP. The original deployment included
only CSAT and ATI-NUW sonics, and when maintenance required replacing an
ATI-NUW sonic by an ATI-K sonic, the sonic height was not changed. The CSAT
sonics did not require maintenance during IHOP.
The sonic anemometer at site 6, ATI-K serial number 980202, output
increasingly high wind speeds beginning around 16:15 CDT, June 17. The
sonic was replaced around 19:00 CDT, June 20. Based on the data, the
problem appears to have been a wind speed offset in the u and/or v paths of
the sonic. Since the turbulent fluxes appear to be unaffected, only the
mean horizontal wind components have been eliminated from the QC sonic
data.
The sonic anemometer originally deployed at site 9, ATI-NUW serial number
7, had an intermittent failure of its "a" path. This sonic was replaced
around 19:00 CDT, May 15. The erroneous sonic data have been eliminated
from the QC data set.
The sonic anemometer data have also been edited to remove data that both
look anomolous and also have concurrent diagnostic warning flags set by the
sonic firmware. For the CSAT3 sonics this required that both bits 14 and 15
in the fourth word of the data message were set high during at least one
sample within a 5-minute period. These bits indicate poor signal lock (bit
14) and a difference in the speed of sound between the three measurement
axes greater than 2.36 m/s, equivalent to about a 4 �C difference in
inferred temperature (bit 15). For the NUW and ATIK sonics this required
that the number of pulses per data sample per axis dropped below the set
value, generally 11 pulses per data sample.
The coordinates of the three-dimensional sonic wind data have been rotated
during data post-processing to align the vertical axis of the sonic
anemometers normal to the mean wind field and to align the horizontal axes
with geographic coordinates (u is a wind from the west, v is a wind from
the south). The tilt angles for each sonic have been estimated from its
wind data using the planar fit technique. The tilt angles, as well as the
calculated vertical velocity offset, are tabulated in the logbook for each
sonic. This table also includes the azimuths of the sonic booms.
Site characteristics
Nine ISFF Flux-PAM stations were deployed in 3 groups of 3 stations.
Each group of three stations corresponded to an IHOP flight track. Stations
1-3, comprising the West leg, were aligned south to north in the Oklahoma
panhandle. Stations 4-6, comprising the Central leg, were aligned roughly
west to east, southwest of Wichita, Kansas. Stations 7-9, comprising the
East leg, were aligned roughly west to east, southeast of Wichita.
For detailed information on siting, instrumentation, and algorithms used
during the IHOP project, and for information on, and to access, data and
parameters not included in this IHOP 5-minute surface composite
see the
NCAR ATD ISFF web page (NCAR/ATD/ISFF, cited
2003).
This data set contains 5-minute resolution surface meteorological
data from the West Texas Mesonet operated by Texas Tech. The West
Texas Mesonet includes 31 stations in the region around Lubbock, Texas.
Instrumentation
Each mesonet station consists of a fenced 10x10 meter plot of land,
10 meter tower, solar panel, RF modem and antenna.
Instrumentation for a basic mesonet station follows:
For more information see the
West Texas Mesonet home page (Texas Tech
University, cited 2003).
For information on, and to access, data and parameters not included in
this IHOP 5-minute surface composite, see the
IHOP_2002
Mesonet: Texas West Texas Mesonet Data [Texas Tech] dataset
For information on the calculation of parameters derived by UCAR/JOSS
from the raw parameters available, see Section 2.2
.
The USDA Agricultural Research Service (ARS) has measured hydrologic conditions
in the Little Washita Watershed in southwestern Oklahoma since 1961. In 1994,
the ARS began monitoring the meteorological conditions in this watershed with an
automated network called the ARS Micronet.
The ARS Micronet is operated and maintained by the USDA Agricultural Research
Service's Grazinglands Research Laboratory in cooperation with Oklahoma State
University and the Oklahoma Climatological Survey. The ARS Micronet is located
within the larger Oklahoma Mesonet, which is operated by the Oklahoma
Climatological Survey.
The support and cooperation of area landowners, without which the ARS Micronet
and related research would not be possible, is acknowledged and greatly
appreciated. As a result of the cooperation between landowners and the ARS,
progress in agricultural and hydrological research has been made possible.
There are 41 ARS stations included within this IHOP 2002 Five Minute
Surface Composite. These stations are all located in the Little Washita
Watershed in southwestern Oklahoma.
Instrumentation and Algorithms
Temperature
The average air temperature is measured at a height of 1.5 meters above the
ground using a thermistor sensor. This sensor is quite rugged and accurate.
However, power and cost limitations dictated using an unaspirated radiation
shield. Unfortunately, such shields can create temperature errors of several
degrees Celsius when the wind is calm (less than 1 m/sec) and radiation is
strong (more than 800 Watts per square meter). Radiation at high sun angles near
70 degrees seem to induce the worst errors. The temperature reported is an
average of the five minutes previous to the report time.
Dewpoint
The average relative humidity is measured at a height of 1.5 meters above the
ground during the last 5-minute interval before the time designated on the
record. Relative humidity changes when either the moisture content of the air
or the air temperature changes.
Relative humidity is measured using a Sorption Sensor. The sensor can detect
relative humidity (RH) between 0 and 100%. The error for readings of 0 - 90% RH
is 2%, while readings of 90 - 100% RH have a 3% error.
Dewpoint temperature was computed by UCAR/JOSS from station pressure,
temperature, and relative humidity using the formula from
Bolton (1980).
Precipitation
The total amount of rainfall is measured
just above the ground in discrete tips of the bucket (approximately
0.01 inch per tip, or 0.254 mm) using a Tipping-Bucket Rain Gauge.
The Mesonet uses an unheated tipping-bucket rain gauge with a 30 cm diameter
opening 0.6 m above the ground. The gauge works by funneling rainfall into one
of two small buckets mounted on either side of a balance pivot. As each bucket
fills, tips, and brings the other bucket beneath the funneled rain, the tip is
counted (one tip is 0.254 mm or 0.01" of rain). Precipitation reported by
UCAR/JOSS is the precipitation collected during the five minutes previous to the
record time.
If the rainfall is very light, the bucket may only tip once every half hour or
so. Thus, even if the rain is continuous, rainfall might be recorded during
every sixth 5-minute interval. If the rainfall is very heavy, there is a strong
likelihood that rain has splashed out of the bucket. Thus, measurements during
heavy rainfall periods generally underestimate the total amount of rainfall.
Unheated gauges were chosen because of constraints on cost and power; the
drawback is that unheated gauges underestimate snow or freezing rain totals. In
addition, wet snow can clog the bucket while dry snow often blows away.
Therefore, do not rely on the gauge observations during frozen precipitation
events. Moreover, once air temperatures rise above freezing, the water
equivalent of the melting precipitation is finally measured. The result is a
delayed measurement of winter precipitation.
For more information on ARS data, instrumentation, and siting, see the
ARS Micronetwork
web site (USDA/GRL, 2003).
Disclaimer
The ARS Micronet data of the Little Washita River Watershed are accepted
and used by the recipient upon the express understanding that the ARS and
it's employees make no warranties, expressed or implied, concerning the
accuracy, completeness, reliability or suitability for any one purpose, and
that ARS and it's employees shall be under no liability to any person by
reason of any use made thereof.
The ARS requests that the recipient of the ARS Micronet data does not
distribute, publish or disseminate the data under the recipient's name
without full and up-front acknowledgement of the ARS as the source of the
data, and that the recipient acknowledges the support and role of the ARS
in publications that use and are based on the ARS data. The data can be
requested from the ARS Micronet Data manager at USDS-ARS, 7207 W. Cheyenne
St., El Reno, OK 73036.
For information on, and to access, data and parameters not included in
this IHOP 5-minute surface composite, see the
OKMESO Little Washita Micronet and Soil Data [USDA/ARS] dataset
For information on the calculation of parameters derived by UCAR/JOSS
from the raw parameters available, see Section 2.2
.
This dataset is formed by extracting 5-Minute Surface Meteorological
Data from the IHOP_2002 Mesonet 1-Minute Surface Meteorological Composite.
Refer to the
IHOP_2002 Mesonet 1-Minute Surface Meteorological Composite
description document for more information.
The following networks were extracted from the 1-Minute Surface
Meteorological Composite: Automated Surface Observing System (ASOS),
Department Of Energy (DOE) Atmospheric Radiation Measurement (ARM)
Southern Great Plains (SGP) Surface Meteorological Observation System
(SMOS) [ARMSFC], DOE Atmospheric Boundary Layer Experiments (ABLE)
Automatic Weather Station (AWS), National Center for Atmospheric Research
Atmospheric Technology Division (NCAR/ATD) Supplemental Surface
Meteorological data (NCAR_supp), and the NCAR/ATD Homestead Integrated
Sounding System (ISS) observation stations.
A 5-Minute file is created from a 1-minute file by summarizing the 5
1-minute observations as follows:
A 5-minute average is calculated from the 1-minute averages provided that
at least 4 valid 1-minute averages are available. No record will be
written to the output file if more than one observation is missing in
the 5-minute interval.
Wind Direction, Speed, and Gusts:
A 5-minute average is calculated from the last two 1-minute averages for
the 5-minute time period. If either of these two 1-minute averages are
missing, then wind direction, speed, and wind gusts will be set to missing.
The IHOP 2002 Five Minute Surface Composite observation 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. For this five munite
surface composite, reported nominal time and actual time are the same.
Days begin at UTC 0100 and end at UTC 0000 the following day. The table
below details the data parameters in each record. Several data parameters
have an associated Quality Control (QC) Flag Code which are assigned by the
Joint Office for Science Support (JOSS). For a list of possible QC Flag
values see the Quality Control Section 3.0.
This dataset contains all five minute observations for the IHOP 2002
domain and time period.
The component datasets from which this dataset was
compiled are available on-line in native format via the
IHOP 2002 master table of datasets (UCAR/JOSS,
2003)
Calculated Sea Level pressure is computed from station pressure,
temperature, dewpoint, and station elevation using the formula of
Wallace and Hobbs (1977).
When not present in the raw data, the dewpoint temperature was
computed by UCAR/JOSS from station pressure, temperature, and relative
humidity using the formula from Bolton (1980).
This calculation was done
for the following networks: Oklahoma Mesonet, NCAR/ATD/ISFF, and ARS.
This IHOP 2002 Five Minute Surface Composite does not contain any Sea Level
Pressures.
The occurance for station ARS 151 should have been set to one in this
composite.
The IHOP 2002 Five Minute Surface Composite was formed
from several datasets. These IHOP 2002 Five Minute Surface Composite
datasets were collected over the IHOP 2002 domain (i.e., 32N to 42N
latitude and 90W to 105W longitude) and time period (13 May 2002 through
25 June 2002) and were combined to form a surface composite. The composite
was quality controlled to form the final IHOP 2002 Five Minute Surface
Composite.
During the JOSS Horizontal Quality Control (JOSS HQC) processing,
station observations of pressure, temperature, dew point, wind speed and
wind direction were compared to "expected values" computed using an
objective analysis method adapted from that developed by
Cressman (1959) and
Barnes (1964). The JOSS HQC method allowed for short term (>/= 30 day)
variations by using 30 day standard deviations computed for each parameter
when determining the acceptable limits for "good", "questionable", or
"unlikely" flags. "Expected values" were computed from inverse distance
weighted station observations within a 200 km Radius Of Influence (ROI)
centered about the station being quality controlled (the station being
quality controlled was excluded); i.e.;
theta_e = < theta(i)/w(i) > / < w(i) >
Where theta_e is the "expected value" of the parameter at the site in
question, theta(i) is the observed value of the parameter at site i, w(i)
is the weighting factor for site i (here the inverse of the distance
between site i and the station being quality controlled), and <...> is
the sum over all stations "i" in the current ROI that have valid
observations of the parameter at the time in question. Data were
always compared at like solar times.
To determine an observation's HQC flag setting, the difference between
the actual observation and its "expected value" was compared to that
parameter's normalized standard deviation. Normalizing factors (also
called the sensitivity coefficients) were chosen to control the "good",
"questionable", and "unlikely" flag limits for each parameter. See
Table 3-1 for IHOP 2002 normalizing factors. Table 3-2
contains the HQC flag limit ranges derived from the normalizing factors
given in Table 3-1 and estimated standard deviations for each parameter
so that 95% of the QC limits applied to the IHOP 2002 data
fell within these ranges. For example, 95% of the observed station
pressure values that were flagged as "good" were within 1.1 mb of the
expected value. The significant overlap of the ranges seen in
Table 3-2 was partially due to seasonal and station differences in
standard deviations. The actual HQC limits applied at any particular
time depended upon the dynamic nature of the particular station's
parameter values over time.
Data were never changed, only flagged.
HQC was only applied to station pressure, sea level pressure,
calculated sea level pressure, temperature, dew point, wind speed and
wind direction. If the calculated sea level pressure quality control
information was available, its flag was applied to the station and
sea level pressures. If the calculated sea level pressure could not
be quality controlled, the sea level pressure quality control flag
was applied to the station pressure. If the sea level pressure could
not be quality controlled, the station pressure quality control flag
was not overridden.
Table 3-1 Normalizing factors used for IHOP 2002 Five Minute
Surface Composite
Table 3-2 Ranges of HQC flag limit values for IHOP 2002
Five Minute Surface Composite
The squall/gust wind speed data were not quality controlled.
There are no Sea Level Pressure values within this IHOP 2002 Five Minute
Surface Composite.
General consistency checks were also applied to the dry bulb
temperature, wind direction, and the relationship between precipitation and
cloud amount/cloud cover. If the dew point temperature was greater than the
dry bulb temperature both values were coded "questionable". Also, wind
direction for observed "calm" winds was given the same QC code as the wind
speed. If precipitation was reported, but the cloud amount was "none" or
"clear", then both the cloud amount and precipitation values were coded
"questionable".
Several impossible values were also checked. Negative wind speeds
were coded "unlikely". Negative squall/gust wind speeds were coded
"unlikely". Wind directions of less than 0 degrees or greater than 360
degrees were coded "unlikely". If these consistency checks would have
upgraded the quality control flags previously set by HQC or gross limit
checks, then they were not applied. However, if these consistency checks
would have degraded the previously set QC flags, they were applied.
The JOSS HQC scheme relied on spatial and temporal continuity to
flag the data. It has been shown that this method works very well for
temperature, dew point, pressure, and wind speed, but is not a very good
scheme for the wind direction. The flags appear to be overly lax and
perhaps could be tightened.
Gross limit checks were also used to determine the quality of the
precipitation values. The gross limits are shown in Table 3-3. Certain
"questionable" and "unlikely" data values were also manually inspected.
After inspection, the quality control flag may have been manually modified
to better reflect the physical reasonableness of the data. Data were never
modified, only flagged. Negative precipitation was also coded "unlikely".
See Table 3-4 for a list of the possible quality control flags and their
meanings.
Table 3-3 - Precipitation Gross Limit Values
Table 3-4 - Quality Control Flags
Barnes, S. L., 1964: A technique for maximizing details in numerical
weather map analysis. J. Appl. Meteor., 3, 396-409.
Bolton, D., 1980: The computation of equivalent potential temperature.,
Mon. Wea. Rev., 108, pp 1046-1053.
Cressman, G. P., 1959: An operational objective analysis system.
Mon. Wea. Rev., 87, 367-374.
NCAR/ATD ISFF, cited 2003: NCAR Integrated Surface Flux Facility at
IHOP2002 [Available online from
http://www.atd.ucar.edu/rtf/projects/ihop_2002/isff/]
Oklahoma Mesonet, cited 2003: [Available online from
http://okmesonet.ocs.ou.edu]
Shafer, M.A., T. Hughes, and J.D. Carlson, 1993: The Oklahoma Mesonet:
Site Selection and Layout. Eighth Symposium on Meteorological
Observations and Instrumentation, Anaheim, CA, Amer. Meteor.
Soc., 231-236.
Texas Tech University, cited 2003: West Texas Mesonet home page
[Available online from
http://www.mesonet.ttu.edu/]
UCAR/JOSS, cited 2003: IHOP Master Table of Datasets [ Available online f
rom
http://www.joss.ucar.edu/ihop/dm/archive/index.html]
USDA/GRL, cited 2003: United States Department of Agriculture,
GrazingLands Research Laboratory ARS Micronetwork [Available online from
http://grl1.grl.ars.usda.gov/micronet/]
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.
2.0 Detailed Data Description
2.0.1 Oklahoma Mesonet Algorithms
Sensor: R.M. Young 5103 Propeller Vane Anemometer
Measures: WSPD, WVEC, WDIR, WDSD, WSSD, WMAX
Height: 10 m AGL
Interval: 3-second sampling, averaged over 5 minutes
(WMAX is highest of the 3-second samples in
the 5-minute interval)
Characteristics: Speed: 1-60 ms; Direction: 0-355 -1 E
Inaccuracy: Speed: 2% reading; Direction: 3 E
Resolution: Speed: 0.03 ms; Direction: 0.05 -1 E
Sensor: Vaisala HMP35C temperature thermistor and sorption
humidity sensor
Measures: TAIR, RELH
Height: 1.5 m AGL
Interval: 3-second sampling, averaged over 5 minutes
Characteristics: Temperature: -30- 50 E C; Humidity 0 - 100% E
Coastal Climate unaspirated 12-plate type radiation shield
Inaccuracy: Temperature: 0.35C; Humidity 3% E
Resolution: Temperature: 0.01C; Humidity 0.03%
Sensor: Vaisala PTB202 Barometer
Measures: PRES
Height: 0.75 m AGL
Interval: 12-second sampling, averaged over 5 minutes
Characteristics: 700-1100 mb
Inaccuracy: 0.4 mb
Resolution: 0.01 mb
Sensor: Metone 099M Tipping Bucket Rain Gauge
Measures: RAIN
Height: 0.6 m AGL
Interval: Accumulated tips over 5 minutes
Characteristics: 30-cm Gauge, 0.25-mm bucket; Alter style wind screen
Inaccuracy: 1% reading
Resolution: 0.25 mm
at 0.6 m
Rainfall (RAIN)
at 0.75 m
Barometric Pressure (PRES)
at 1.5 m
Air Temperature (TAIR)
Relative Humidity (RELH)
at 10 m
Wind Speed (WSPD)
Direction (WDIR)
Maximum Wind Gust (WMAX)
2.0.2 National Center for Atmospheric Research (NCAR) Atmospheric
Technology Division (ATD) Integrated Surface Flux Facility (ISFF)
Algorithms
* Vaisala 50Y Humitter to measure air temperature and RH; in NCAR aspirated
radiation shield at 2 m agl
* Barometer, Vaisala PTB220B, with a Ser single-disk static pressure port
* MRI model 302/303/304 tipping bucket rain gauge, with Alter wind screen at
sites 1-3
* Sonic anemometer, initially either Campbell CSAT3 or ATI-NUW
* zs = 2.7 m for the CSAT3 sonic
* zs = 4.0 m for the ATI-K sonic
* zs = 4.6 m for the ATI-NUW sonic
* D = canopy zero-plane displacement, estimated as 2/3 the height of the
vegetation
Sonic Heights
Site 1 2 3 4 5 6 7 8 9
Height, m agl 2.5 3.43 2.7 2.6 5.0 4.9 2.7 4.6 4.7
2.0.3 Texas Tech West Texas Mesonet (WTXMESO)
2.0.4 United States Department of Agriculture (USDA) Agricultural Research
Service (ARS) Micronet
2.0.5 IHOP_2002 Mesonet 5-Minute Surface Extract from IHOP_2002 Mesonet
1-Minute Surface Meteorological Composite
Parameter Summarization technique
-------------------------------------------------------------------------
Cloud Height Use amount reported at each 5-minute interval
Visibility Use amount reported at each 5-minute interval
Precip Total over the 5 1-minute periods
Temperature Average over the 5 1-minute periods
Dew Point Average over the 5 1-minute periods
Wind Dir/Speed Break into components, average components
over last two 1-minute periods, compute new vector
Wind Gust Greatest value in last two 1-minute periods
Station Pressure Convert altimeter setting to station pressure;
average over 5 1-minute periods
Sea Level Pressure Average over the 5 1-minute periods
2.1 Detailed Format Description
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
Parameter Good Questionable Unlikely
--------- ---- ------------ --------
Station Pressure 0.2 0.2 0.5
Calculated SLP 0.4 0.4 1.0
Dry Bulb Temperature 0.5 0.5 1.0
Dew Point Temperature 0.5 0.5 1.0
Wind Speed 2.25 2.25 4.0
Wind Direction 1.22 1.22 2.2
Parameter Good Questionable Unlikely
--------- ---- ------------ --------
Station Pressure (mb) < 1.1 [0.5-2.7] > 1.3
Calculated SLP (mb) < 3.0 [1.1-7.4] > 2.8
Dry Bulb Temperature (deg.C) < 3.0 [1.2-6.0] > 2.5
Dew Point Temperature (deg.C) < 2.7 [1.0-5.4] > 2.0
Wind Speed (m/s) < 7.6 [1.6-13.6] > 2.8
Wind Direction(degrees) < 120.5 [54.6-180.0] >98.4
Parameter Good Questionable Unlikely
--------- ---- ------------ --------
1 Minute Precip < 6.0 mm >= 6.0 mm >= 11.0 mm
QC Code Description
------- -----------
U Unchecked
G Good
M Normally recorded but missing.
D Questionable
B Unlikely
N Not available or Not observed
X Glitch
E Estimated
C Reported value exceeds output format field size or
was negative precipitation.
T Trace precipitation amount recorded
I Derived parameter can not be computed due to
insufficient data.
4.0 References