Surface Meteorological and Upper-Air Data Collected by five Integrated Sounding Systems (ISS) During the TOGA COARE Intensive Observing (IOP) and EMP
Entry ID:
COARE_lsa_ISS
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Summary
Abstract:
DATA ACCESS Quality-controlled surface meteorological data are available from FSU/COAPS at http://www.coaps.fsu.edu/COARE/. Quality-controlled upper-air soundings data are available through the WWW/CODIAC at http://data.eol.ucar.edu/codiac/ SUDS-generated skew-t plots and analysis files for TOGA COARE Integrated Sounding System (ISS) upper-air data are available via the NCAR/ATD WWW server at ... http://www.atd.ucar.edu/sssf/sndg_arc/day_toga_coare_0.html .
TOGA COARE BACKGROUND
TOGA COARE was a multidisciplinary, international research effort that
investigated the scientific phenomena associated with the interaction
between the atmosphere and the ocean in the warm pool region of the
western Pacific. The field experiment phase of the program took place
from 1 November 1992 through 28 February 1993 and involved the
deployment of oceanographic ships and buoys, several ship and land
based Doppler radars, multiple low and high level aircraft equipped
with Doppler radar and other airborne sensors, as well as a variety of
surface based instruments for in situ observations.
Six Integrated Sounding Systems (ISS) were installed and operated for
various lengths of time during the TOGA COARE Intensive Observing
Period (IOP) and Enhanced Monitoring Period (EMP). The ISS was
developed jointly by the Surface and Sounding Systems Facility of the
National Center for Atmospheric Research Atmospheric Technology
Division and the Aeronomy Laboratory of the National Oceanic and
Atmospheric Administration. The ISS combines four separate subsystems:
- Balloonborne radiosonde navaid (Loran or Omega) sounding system
- Enhanced surface observing station
- 915 MHz Doppler clear-air wind profiling radar
- Radio Acoustic Sounding System (RASS).
A complete description of the ISS is available from
http://www.atd.ucar.edu/sssf/facilities/sssf_facility_descrip/ISS.s....
The ISSs were located at Kavieng and Manus Island (Papua New
Guinea), Nauru (Republic of Nauru), Kapingamarangi (Federated States
of Micronesia), and on two research vessels, Shiyan #3 (Experiment #3)
and Kexue #1 (Science #1).
ISS soundings are available for the following time periods:
Kapingamarangi (FSM), WMO#91434
IOP: 00 06 12 18 UTC
EMP: 00 12 UTC
Data available: 110792-290693
Kavieng (PNG), WMO#94076
IOP: 00 06 12 18 UTC
Data available: 011192-010393
Manus (PNG), WMO#94044
IOP: 00 06 12 18 (IOP)
Before 1 Nov 92: 00 UTC
After 1 Mar 93: 00 12 UTC
Data available: 010792-270992, 181092-301192, 241293-220193, 280193-300693
Nauru, WMO #91530
IOP: 00 06 12 18 UTC
EMP: 00 12 UTC
Data available: 020992-300693
R/V Kexue #1
IOP: 00 06 12 18 UTC
Data available: 091192-111292, 151292-230193, 280193-190293
R/V Shiyan #3
IOP: 00 06 12 18 UTC
Data available: 101192-111292,181292-220193,260193-180293
1. Surface Data
The ISS surface meteorological instrument installation includes
several sensors mounted on two separate towers as well as a rain gauge
mounted independently. An anemometer is mounted on the top of a
ten-meter tower. Temperature and humidity sensors are mounted on the
end of a one-meter boom attached to the ten-meter tower at two meters
above the surface. The temperature and humidity sensors are aspirated
and protected with a radiation shield. The pressure sensor is housed
in the box containing the Campbell CR 10 datalogger. That box is
mounted on the ten-meter tower at one meter above the surface.
The radiation sensors are mounted on a one-meter boom on the top of a
separate two-meter tower. The standard ISS radiation sensors include
an up-looking solar radiation sensor and a net radiation sensor. In
situations which require more complete radiation measurements,
additional sensors can be added.
The output from all the sensors is directed to the Campbell datalogger
for processing. The Campbell datalogger, which is independently
programmable, typically generates one-minute average data which are
sent via RS-232 to the ISS Sun workstation. The data input to the
Campbell datalogger are five-second sample data.
Florida State University under the direction of Dr. James O'Brien and
Dr. David Legler, produced a comprehensive TOGA COARE surface
meteorological dataset, which includes the quality-controlled ISS
surface met data. Data, which are in netCDF as well, can be accessed
through the WWW ( http://www.coaps.fsu.edu/COARE/ ). The quality
control process was executed in two steps. All surface meteorological
data were assessed beginning with a low-level scan. This scan
included, at a minimum, automated checks for coding errors, spurious
spikes, instrument drift or failure, and unrealistic values. Each data
record from each platform was visually inspected and all data points
were flagged as either passing or failing the low-level
inspection. The second step in the QC process will be the
inter-comparisons of data across platforms/instruments. Comparisons
between these data will be exploited to verify the data from the
platforms and differences noted.
2. Upper-air Data
The balloonborne radiosonde navaid (Loran or Omega) sounding system is
the standard NCAR "CLASS" sounding system. This sounding system
typically uses the Vaisala RS-80 L or the Vaisala RS-80 N radiosondes
which use Loran and Omega radionavigation signals respectively for
windfinding. Launching configurations can vary depending on the
installation. An ISS site may have an enclosed air conditioned
launcher, a "bag" launcher, or possibly no launcher at all. The
balloon and sonde are secured to structures available before release
in the latter case.
Final, quality-controlled upper-air data are available from UCAR/OFPS
though the CODIAC system, http://data.eol.ucar.edu/codiac/. The
data have passed through the JOSS Quality Control process after the
original data were converted into the JOSS Quality Control (ASCII)
Format (QCF). Data were processed, quality controlled and archived in
the highest "native" resolution. JOSS' QC process consists of three
stages: a) automatic internal consistency checks, which include 17
automatic checks to evaluate the internal consistency of each
individual sounding ("reasonable limit" check); b) vertical
consistency checks which include comparisons between adjacent vertical
levels; c) visual examination of each sounding. To establish the
consistency of upper air measurements across the entire COARE domain,
spatial quality of the sounding data was assessed by comparing
neighboring data. The general methodology used by JOSS is to produce
statistics (mean, standard, deviation, variance) from a simple
weighted averaging technique.
This dataset underwent significant processing by NCAR/SSSF prior to
its arrival at OFPS. The reprocessing efforts and documentation files
regarding the quality of each sounding are available for each sounding
location from the TCIPO and UCAR/JOSS.
3. SUDS-generated skew-t plots and analysis files for TOGA COARE
ISS upper-air data
SUDS-generated skew-t plots and analysis files for TOGA COARE ISS
upper-air data are available from NCAR/ATD. Since sounding data for a
project are gathered across many days from several stations, the
NCAR/ATD archive organizes the information in two ways, by day and by
station. For a given project, all of the sounding information for a
date are grouped together in the "by day" documents, and all of the
information for a station are grouped together in the "by station"
documents. Moreover, to make the archive more usable, each sounding
reference has a color identification that indicates the sounding's
launch station.
For more information, contact David Ecoff at NCAR/ATD
(ecoff@ucar.edu). 
Geographic Coverage
(Click for Interactive Map)
Spatial coordinates
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N: 30.0
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S: -30.0
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E: 180.0
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W: 120.0
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Temporal Coverage
Start Date:
1992-07-01
Stop Date:
1993-06-30
Quality
INDIVIDUAL SITE & SHIP SURFACE DATA
1. Kapingamarangi Station
+ Surface Humidity Data: The humidity sensor failed at Kapingamarangi
at 16Z on the 17 November 1992 and, due to shipping problems, it was
not replaced until 02 February 1993. There are portions of good data
after 17 November, as the sensor began to ... drop out intermittently at
that time. After the 25 November at 06Z there were no good humidity
data. A replacement humidity sensor and a psychrometer were sent to
Kapingamarangi. The psychrometer arrived before the replacement
sensor. Psychrometer data were taken but recorded separately beginning
4 January 1993 at 17Z. The data were taken every hour through the end
of February (with a number of gaps). That data are available in ASCII
format. They are tabulated by date and sounding time (sounding times
are GMT). The data format is: local time (GMT + 11)-Temperature-Wet
Bulb Temperature-.....
+ Surface Pressure and Temperature Data: The surface pressure data
appear noisy at times. This can be seen in the time series plots as a
series of a few points offset up to one millibar from the mean
pressure trace. This is seen over several time periods: 9-15 December
1992; 14-19 January 1993; 7 February 1993; 10-15 February 1993; 27
March - 22 April 1993; and 25-31 May 1993. There are a few erroneous
spikes in the temperature data. Most of these occurred 19-23 February
1993.
+ Surface Data Gaps: There are several data gaps when no surface data
were recorded. These were caused by various things - short term disk
problems, power interruptions, etc. The gaps are 23-26 August 1992
(72 hours); 3-6 October 1992 (60 hours); 15-16 October 1992 (20
hours); 5 December 1992 (7 hours); 8 March 1993 (4 hours); 21 April
1993 (20 hours); and 21 June 1993 (21 hours). There were other shorter
data gaps as well. These were typically on the order of two hours or
less.
+ Results from FSU Quality Control: Some variables in these data are
considered to be in poor condition. Several problems occurred in the
pressure data. A preprocessing program flagged many values as either
out of the acceptable range or for being greater than four standard
deviations away from the da Silva climatological mean (da Silva, et
al. 1994). Numerous discontinuities occurred just after small breaks
in the data and were flagged as suspect data. Finally, rhythmic
spikes occurred on many days. These one millibar, downward spikes
usually occurred near the even hour and in some cases lasted for
several days. These values were flagged as spikes although they may
be the result of a data logger or instrument malfunction.
As noted in the ISS Report (Miller 1994), the humidity sensor, in a
Vaisala Humicap Model HMP35C, began malfunctioning at 16Z on the 17th
of November, 1992 and was not replaced until the 2nd of February,
1993. Normal relative humidity values for Kapingamarangi are in the
range of fifty to ninety percent, however, the humicap started
reporting values between ten and fifty percent. The drops to the
lower relative humidity values were very abrupt, often occurring in
one or two minutes. It is notable that the relative humidity trends
were still realistic (i.e. the diurnal cycle was present in the data)
even though the absolute value of the relative humidity was
unrealistically low. The relative humidity data were flagged during
these periods as a malfunctioning sensor.
Because the temperature sensor and humidity sensor are coupled in an
HMP35C, many temperature values were flagged as suspect data or as a
malfunction. Other suspect data flags were added to interesting
discontinuities which occurred just after temperature values were out
of the realistic range. These flags were usually associated with the
discontinuities which occurred in the data.
The wind direction, wind speed, and precipitation data do appear to be
in very good condition, and there were 26 days that had no flags
added.
2. Kavieng Station
+ Surface Pressure Data: The surface pressure sensor did not operate
correctly from start-up through 00Z 16 November 1992. A replacement
was installed at that time and performed reliably through the
remainder of the project.
+ Surface Data Gaps: There were a few gaps in the surface data at
Kavieng. The longest gap ran from 5 November at 08Z until 16 November
1992 at 00Z. There were two other significant gaps, one from 16Z 6
December until 00Z 7 December 1992, and one from 00Z until 20Z on 22
December 1992.
+ Radiation Data: During January 1993, the up-looking and down-looking
pairs of pyranometers and pyrgeometers were switched (a standard
practice to detect any bias in the instruments). The up-looking
pyranometer became the down-looking pyranometer and vice-versa. The
up-looking pyrgeometer became the down-looking pyrgeometer and
vice-versa. However, due to a number of factors, things were not
switched properly (both hardware and software) and some confusion
resulted. Corrected data from this period can be obtained from the ARM
PROBE archive; contact Chuck Pavloski (pavloski@essc.psu.edu). Note
that two data fields in the Kavieng surface data files are not used.
The information in them should be ignored. These fields are sol and
soldiff (Kavieng only!).
+ Results from FSU Quality Control: The data from Kavieng are in very
good condition, however, two main problems occurred during the
IOP. The primary reason for flags was a malfunctioning atmospheric
pressure sensor which reported a constant pressure of 800 mb from 0000
UTC on November 1, 1992 through 2400 UTC on November 4, 1992. No
pressure data were available from 0000 UTC on November 5, 1992 through
2400 UTC on November 15, 1992. The sensor was replaced and the new
sensor appeared to function properly from 0000 UTC on November 16,
1992 through the end of the IOP (Miller 1994). The second problem was
the lack of data from 0000 UTC on November 5, 1992 through 2400 UTC on
November 15, 1992. Data were not collected for any of the variables
for these eleven days.
The data analyst does not foresee any problems in using this data.
The 22 interesting feature flags were added to the wind direction,
wind speed, temperature, and relative humidity profiles to highlight
what are believed to be convective events (TCIPO 1993) which produced
dramatic changes in these variables. Satellite imagery was used to
identify these events. Flags were placed at peak wind speeds and the
corresponding directions and at the beginnings and ends of significant
drops or rises. Minor changes were noticed in other variables but
were not flagged.
3. PRC R/V Kexue 1 (Research Vessel)
+ Earth-relative Surface Wind Data: The shipboard surface wind
measurements were made with the standard RM Young Wind Monitor. They
were corrected for ship motion using ship speed obtained from a GPS
navigator and ship direction (heading of the ship's longitudinal axis)
obtained from a magnetometer. The GPS direction (obtained from ship
position differencing) was not adequate for use with the wind
algorithm when the ship was "on site" (anchored or drifting).
Comparisons of the magnetometer data to the GPS directional data
during cruises have generated some concern regarding the operation of
the magnetometer. In comparisons done for the PRC R/V Kexue 1,
differences in the two directions have been seen to vary, at times as
much as 20 degrees. This was the case after magnetic declination was
taken into account. Thus there is an unknown uncertainty in the wind
direction measurement. In addition to the magnetometer uncertainty,
there were periods when the GPS navigator failed. During these periods
the surface wind data were not corrected for ship motion. The
uncorrected wind data are available but they will be of limited
use. The direction will be bad (unless the longitudinal axis of the
ship happens to be pointing to the north). The speed may be useful if
the ship isn't moving or is only moving very slowly relative to the
real wind (often the case when the ship was on station). Periods when
the GPS failed and no corrected winds were obtained are 1-9 November
1992 (prior to first deployment on station); 13-14 December 1992 (44
hours); and 11-28 January 1993 (17 days).
+ Surface Pressure and Temperature Data: There were a few long periods
of noisy surface pressure data. This can be seen in the time series
plots as a series of a few points offset up to one millibar from the
mean pressure trace. The times when this occurred are 25 November
through 13 December 1992; 16-25 December 1992; and 13-17 January
1993. Much of the surface temperature data from the PRC R/V Kexue 1 is
noisy. Most of the temperature data recorded after 00Z on 20 November
1992 show a variance which is too high. Use caution when using this
data. Some sort of averaging would likely salvage some useful
information.
+ Surface Data Gaps: There was very little lost data from the PRC R/V
Kexue 1. The only significant data gap occurred from 09Z until 22Z on
15 December. There were a few other much shorter (on the order of two
hours) data gaps, but overall the data recording system performed
quite well.
4. PRC R/V Shiyan 3 (Research Vessel)
+ Earth-relative Surface Wind Data: The shipboard surface wind
measurements were made with the standard RM Young Wind Monitor. They
were corrected for ship motion using ship speed obtained from a GPS
navigator and ship direction (heading of the ship's longitudinal axis)
obtained from a magnetometer. The GPS direction (obtained from ship
position differencing) was not adequate for use with the wind
algorithm when the ship was "on site" (anchored or
drifting). Comparisons of the magnetometer data to the GPS directional
data during cruises have generated some concern regarding the
operation of the magnetometer. In comparisons done for the PRC R/V
Shiyan 3, differences in the two directions have been seen to vary, at
times as much as 8 degrees. This was the case after magnetic
declination was taken into account. Thus, again, there is some
uncertainty introduced into the wind direction measurement.
+ Surface Pressure, Temperature, and Humidity Data: There were no ISS
surface pressure data from the PRC R/V Shiyan 3 during the first
cruise. The sensor fell overboard during a maintenance effort in rough
seas. A replacement was installed at the first port of call. Recording
of good pressure data resumed at 0330Z 15 December 1992. There were a
couple of short periods of bad temperature and humidity data in
January 1993. Use caution with data obtained between 00Z and 04Z on
both 24 January and 30 January. In addition, there were periods of
noisy temperature data. The temperature data variance was too high
early in the first cruise (12 November 1992) and was also possibly a
bit high in early December 1992.
+ Surface Wind Data: The are periods of very high, spiky wind speed
data in the last half of December. This can be seen in the time series
plots from roughly 17-31 December 1992. Although the data appear
suspect, it is likely that they may be reasonable as they correlate
well with periods of significant rain and may be gusts associated with
storm cells.
5. Manus Station
+ Humidity Data: The first good surface humidity data at Manus was
obtained on 02 October 1992. Prior to that, there were no good
humidity data.
+ Radiation Data Initially, a LICOR radiometer was used to measure
solar radiation. The output of that instrument was in kilowatts per
square meter (kW/m2). That sensor was replaced by an Eppley
pyranometer at the end of October 1992. The output of the Eppley
sensor was in watts per square meter (W/m2). The difference in output
is reflected in the time series plots (the units for the solar
radiation data plots of July through October 1992 SHOULD BE "kW/m2").
There was no longwave (ir) radiation sensor at Manus until 1 November
1992. The Eppley Pyrgeometer installed to measure longwave radiation
(incoming - the sensor was up-looking) functioned properly for the
remainder of the Extended Monitoring Period (through June 1993),
although it was not properly calibrated. The output of the sensor was
about 80% of what it should have been. Comparisons with incoming
longwave radiation data from the nearby Kavieng ISS site showed that
the Manus sensor output was roughly 80% of that obtained at
Kavieng. The Manus pyrgeometer output consistently stayed at that 80%
level throughout the project.
+ Data Loss: There were a few significant periods of complete surface
data loss. There were no surface data obtained from 20 October until 1
November 1992. There were also no data recorded from 16 May 1993
through the end of June 1993 due to disk problems. There were a few
other shorter periods, up to two and one-half days, where data were
lost. These periods are clearly apparent in the time series plots
provided. There were also periods of intermittent surface data in July
1992.
+ Results from FSU Quality Control: The data from Manus are in very
good condition. The only problem that occurred, and the result of
most of the flags, involves the relative humidity data. The 10,440
flags were added to relative humidity values slightly greater than 100
percent. These values may be the result of fog or, possibly, a
miscalibrated relative humidity sensor.
The data analyst does not foresee any problems in using this data.
The 48 interesting feature flags were added to the wind direction,
wind speed, atmospheric pressure, temperature, and relative humidity
profiles to highlight what are believed to be convective events (TCIPO
1993) which produced dramatic changes in these variables. Satellite
imagery was used to identify these events. Flags were placed at peak
wind speeds and the corresponding wind directions and at the
beginnings and ends of significant drops and rises. Minor changes
were noticed in other variables but were not flagged.
6. Nauru Station
+ The surface data quality and recovery from Nauru are quite
good. There were no data recorded until late August 1992. There is a
24 hour period of missing data 6 and 7 November 1992. There are only a
few other short periods, on the order of a couple hours, of missing
surface data. Again, these are apparent from the time series plots
provided.
+ Results from FSU Quality Control: The data from Nauru were
considered to be in good condition except for two problems that
occurred in the pressure data. The first problem was the presence of
rhythmic, one millibar, downward spikes in the atmospheric pressure
data. These spikes were similar to those seen at Kapingamarangi.
They occurred near almost every even hour on many days and sometimes
lasted for periods of up to several days. The other problem in the
Nauru atmospheric pressure data is the large number of values that
were flagged for being greater than four standard deviations from the
da Silva climatological mean (da Silva, et al. 1994). These pressure
values were usually rather low. As a final note, the data analyst
does not foresee any problems in using this data.
Personnel
Role:
DIF AUTHOR
Phone:
+1 917 367 2467
Fax:
+1 212 963 3742
Email:
czaran at un.org
Contact Address:
United Nations
Secretariat Building
UN Plaza
City:
New York
Province or State:
NY
Postal Code:
10017
Country:
USA
Creation and Review Dates
Last DIF Revision Date:
2005-06-14
Future DIF Review Date:
2003-01-05
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