The final data for the International Photolysis Frequency Measurement and Modeling Intercomparison study is due to the referee (Jack Calvert, calvert@ucar.edu) on 1 September, 1998 for the four intensive days (15,16, 18, and 19 June, 1998) from 5:00 to 21:00 MDT. Submit your data by e-mail attachment or mail a PC-compatible diskette. Please carefully read the following information related to the data submittal, since a few details have changed since our discussions in June. Part of this relates to directions given to participants in the modeling portion of this exercise. If you are involved in both, use care to adhere to the protocols for each part. Please contact Chris Cantrell (cantrell@ucar.edu) if you have questions about these instructions.
Averaging Times
To the degree possible, submit photolysis
rate coefficients for all of the three averaging times (1 minute, 10 minutes
and 30 minutes) with the time periods starting on the hour. Give
the time as the start of the averaging period. For example, for the
10 minute averages there will be data for the period 11:00:00 to 11:09:59
labeled 11.0000, for 11:10:00 to 11:19:59 labeled 11.1667, etc. Note
that time stamps are fractional hours (four decimal places) in Mountain
Daylight Time (MDT, MDT = MST +1 = GMT – 6). The times should include all
of the possible averaging periods throughout the intensive (i.e. even if
your instrument is not making actual measurements, include a row for each
time). Average the actinic flux data in a similar fashion for the
periods described below.
The first time for the 1 minute averages corresponds to data from 5:00:00 to 5:00:59 and is labeled 5.0000; the first time for the 10 minute averages corresponds to data from 5:00:00 to 5:09:59 and is also labeled 5.0000; and the first time for the 30 minute averages corresponds to data from 5:00:00 to 5:29:59 and is labeled 5.0000.
File Formats
Submit the photolysis rate data in a Microsoft
Excel spreadsheet shown in this document and in “sample1.xls”, using naming
conventions described below. Each institution should submit 3 files
corresponding to the 1 minute, 10 minute and 30 minute averaging times
for each intensive day. In cases where there are multiple measurements
from the same institution, use separate worksheets within the same file.
For example, NCAR will have data for jNO2 and jO3 from actinometers and
jNO2 and jO3 from their spectroradiometer with calculations performed for
two combinations of NO2 molecular data, two combinations of O3 molecular
data and two temperatures for the O3 molecular data. They will have
eight worksheets in each file. Indicate in the comments the instrument
and/or cross section/quantum yield/temperature combination being used.
The modelers have been directed to use ambient temperatures, while the
comparison between spectroradiometers and actinometers is more meaningful
using the temperature of the jO3 actinometer. Thus, we are asking
the spectroradiometer data to be used with both temperatures for the jO3
calculations.
Indicate the number of measurements and the standard deviation of those measurements for each average in the columns indicated. If there are no data for a given averaging period, leave the measurement and standard deviation columns blank, and put 0 in the number of values column.
Use flags to indicate the quality of the
data:
1 normal
2 may be problems
3 data no good
4 time out for instrument fix or other
reason except calibration
5 limit of detection
6 calibration
For the spectroradiometer actinic flux data, give 10-minute average down-welling flux data at 1 nm intervals (centered on the nm) from 290 to 420 nm in units of photons cm-2 s-1 nm-1 at 6:00, 7:00, 8:00, 9:00, 10:00, 11:00, 12:00, and 13:00 MDT (i.e. average from the hour to 9 minutes 59 seconds past the hour). If there are no data available at a wavelength or time, leave the cell(s) blank. Layout of the Excel worksheets is shown in this document and in “sample2.xls”.
Do your best to correct possible time shifts due to instrument delays, for example, before submittal of the data. If residual time shifts are possible, note those in the comments section of the worksheet.
Ancillary Data
Temperature, pressure and molecular data
for NO2 and O3 to be used to derive j-values from the spectroradiometer
data is provided on the web at http://acd.ucar.edu/~cantrell/ipmmi.html.
Use the various possible combinations to yield two jNO2 values (at ambient
temperature) and four jO3 values (at both temperatures) for each time period.
There will be no comparison of jCH2O since we have no actinometer for this
process.
File Naming Convention
Submit data to the referee via PC-compatible
diskette labeled with your name and institution or via e-mail attachment
with Excel files using the following naming conventions:
IIIDDNNV.xls
Where:
III 3 letter
code for your institution
NCR NCAR
IFU IFU
FZJ Forschungszentrum Julich
NIW NIWA
NAL NASA Langley
UMD University of Maryland
GAT Georgia Tech
NOA NOAA Aeronomy Lab
ULE University of Leicester
MET Meteorolgie Consult
DD Day in June, 1998
15 June 15, 1998
NN Averaging time
01 1 minute averages
10 10 minute
30 30 minute
V Version letter
A first version of final
data
B second version
Summary
To summarize what is expected for data
from the various instruments for the intensive periods:
j-value Radiometers
j-values at 1, 10, and 30 minute averages
Actinometers
j-values at 1, 10, and 30 minute averages
Spectroradiometers
jNO2 for two sets of molecular data (ambient temperature) at 1, 10 and
30 minute averages (two values for each time period).
jO3 for two sets of molecular data at two temperatures (ambient & the
jO3 actinometer) at 1, 10 and 30 minute averages (four
values for each time period).
Actinic flux spectra averages starting on the hour during the morning at
10 minute averages.
Eppley radiometers
Irradiance in milliwatts-cm-2 at 10 minute averages.
Workshop
A workshop will be conducted at NCAR on
Friday, 4 December, 1998 to discuss the data and plan the next stages of
release of the results to the scientific community (papers, AGU sessions,
journal special section etc.). Please contact Marilena Stone (stone@ucar.edu)
to indicate whether you will be able to attend the workshop and your travel
dates so that hotel reservations may be made. No funding is available
for the workshop.