PRP2 CAL-VAL BOULDER CO 4/12-5/3 2013

Transcription

1 PRP2 CAL-VAL BOULDER CO 4/12-5/3 213 Lat: Lon: THIS IS AN INFORMAL LOG OF THE EXPERIMENT AND THE FOLLOW DATA ANALYSIS

2

3 UTC JD LOG 4/1 1 Early flight from Seattle. System was deployed and started. Communication via ssh was established. It had snowed the day before but was melting now. 4/11 11 All good. I checked in on everything, cleaned up and left it running at about 19Z. Returned to Seattle. 4/12 12 All good but cloudy skies limit AOD calculations. 4/13 13 All good. More cloud breaks. 4/14 14 Normal. Good morning for a Langley. 4/15 15 Snow, snow, snow. The FRSR was set to LOW. 4/ / Z (1am) in Boulder, there still is significant snow. FRSR remains in Low mode. -3C air temp. 16: I got a message from Joe that he had cleared off the snow. But I decided to leave the RSR in Low. 16Z(1MST) Web cam indicates more snow. Temps < C so FRSR remains in Low. WX fcst calls for ice & snow today. Improving conditions. 4/ Z(7MST) Temp -12. It s supposed to be below zero and cloudy all day. FRSR remains off. 4/ /2 11 4/ Z(73) Clear but cold, -2C, this morning. But I am going to start the FRSR. 23Z: Joe found that the set screw has slipped in the motor. No doubt because of the snow. Joe removed the motor assy and fedexed it to me. 192Z(1228 MST) Solar radiarion is high, 95 W/m^2, so it looks to be nice and sunny. Too bad, there s no shadowband. I put the FRSR into low mode so at least we ll collect global values to compare. Sunday 17Z, The FRSR motor arrives tomorrow. meanwhile we are having wonderful weather in Boulder. wunder says clear skies and 13 C. Open channel mean = 679 +/-5. Wow. sw = 83 +/- 8. 4/ Monday motor arrives. Fixed but set screw broke off. Had to repair at machine shop. 4/ Tuesday. Check operation. FedEx to Boulder 4/ Arrives in Boulder. Joe installs. Note the cable must be plugged correctly. Good. Begin data collection at 1848Z. Partly cloudy. 4/ All good. Sunny day. FRSR is working well. 4/ Z (8 MST) is perfectly clear. This might be a good day.

4 UTC JD LOG 4/ Set frsr threshold from 1 to 5. 4/26 was a terrific day. 4/ Z (834 mdt) Not such a perfect day, but pretty good. High Ci. 4/ Z (73 mdt) Clear sky but some cloud. All equipment seems to be working well. 4/3 12 chance of rain. 133Z. Morning starts cold and cloudy. Snow is expected tonight so I will need to shut down the band. 26Z+ I put the FRSR into standby. It might snow tomorrow. 5/ Z (544 mdt) It is snowing and temps are <. FRSR is left in low mode. 5/ Z (715 mdt) Joe s things are good. No snow. Clear skies. So I pulled the data and started the FRSR. However, it is -8 C. 5/3 123 partly cloudy. Recover the equipment. Ship to Seattle. 5/6 Data received from Joe as an R file. 5/14 PSP IR analysis and a corrected SW. 5/18 Time to get on this. I filed an ARM IMMS report with acknowledgements.

5 FIELD -- DAY BY DAY

6

7 (14) -- Morning MORNING LANGLEY.4 TOA =.343, Chan 3, 613 nm.3.2 LN NORML ATM MASS

8 (14) -- Morning NOAA MFRSR (14) filter 1,2,3,4,5 = bk,bl,gr,cy,ma HOUR UTC

9 (116) -- Morning (116) 6:8 to (117) 6:24 now = , 1:14 IQBAL:.5, 632,.2,.2,.1 This view from the BAO tower back to Boulder shows an almost perfect morning Day 116 was clear almost all day. Clouds began forming after 22Z. The bottom plot, Chan 4, is of transmissivity (total optical depth, blue) and the AOD (red) after correction for Rayleigh scattering (~.63) and ozone (~). SW plot, red curve is from iqbal where w = integrated water vapor (g/cm^2) p == surface pressure in hpa k1 == AOD at 38 nm k2 == AOD at 5 nm l == ozone-layer thickness in cm(ntp) I guessed at these.

10 (116) -- Morning MORNING LANGLEY.4 TOA =.3697, Chan 3, 613 nm.3.2 LN NORML.1.1 aot_total = ATM MASS

11 (116) -- Morning NOAA MFRSR (116) filter 1,2,3,4,5 = bk,bl,gr,cy,ma HOUR UTC

12 (117) -- AM & PM nm CRUISE CALVAL1, ,12555 to , nm nm nm (117) 6:1 to (118) 4:9 now = , 8: nm IQBAL:.5, 632,.2,.2, nm UTC 213 aod s ummary c alval

13 (117) -- AM & PM MORNING LANGLEY TOA =.4238, Chan 3, 613 nm aot_total =

14 (117) -- AM & PM NOAA MFRSR (117) filter 1,2,3,4,5 = bk,bl,gr,cy,ma HOUR UTC

15 (118) -- AM AOD --.5 CRUISE CALVAL1, ,12437 to , nm nm nm nm (118) 5:3 to (119) 8:9 now = , 6: nm 1 IQBAL:.5, 632,.2,.2, nm UTC 213 aod s ummary c alval

16 (118) -- AM MORNING LANGLEY.4 TOA =.447, Chan 3, 613 nm.3.2 LN NORML aot_total = ATM MASS

17 (118) -- AM NOAA MFRSR (118) filter 1,2,3,4,5 = bk,bl,gr,cy,ma HOUR UTC

18 (119) -- AM nm CRUISE CALVAL1, ,1232 to 21343, nm nm nm nm (119) 8:4 to (12) 5:33 now = , 19:55 1 IQBAL:.5, 632,.2,.2, nm UTC 213 aod s ummary c alval

19 (122) -- AM & PM

20 (122) -- AM & PM NOAA MFRSR (122) filter 1,2,3,4,5 = bk,bl,gr,cy,ma HOUR UTC

21 (123) -- AM

22 (123) -- AM & PM NOAA MFRSR (123) filter 1,2,3,4,5 = bk,bl,gr,cy,ma HOUR UTC

23 LOG (I) Chan 2, TOA =.31, AOD =.256 LOG (I) Chan 2, TOA =.339, AOD =.327 Date aod I_ 4/ / / / / MEAN I_ 1.44 StDev HOUR UTC HOUR UTC LOG (I) Chan 2, TOA =.394, AOD =.34 LOG (I) Chan 2, TOA =.424, AOD =.336 I_ = I_T / r^2 where I_T from Plot r = R / R_ref R(t) = sun-earth distance R_ref = reference distance I_ = TOA beam irradiance when r= HOUR UTC HOUR UTC This is an example for chan 2 (413 nm) of the quality of the Langly plots. We have five good days, 4/14, 4/26, 4/27, 4/28, and 4/29.The projected TOA irradiance, I_T, must be corrected for comparison with the reference TOA value, I_.

24 FRSR LANGLEY ANALYSIS CHAN Lgly std Ref std %diff * * Channel 7 is strongly influenced by column water vapor and is generally neglected for AOD calculations.

25 NOAA LANGLEY RESULTS CHAN wavelen V std(v)

26 ANALYSIS -- OPTICAL DEPTH

27 ANALYSIS -- OPTICAL DEPTH FRSR CHANNEL IRRADIANCE (99) 23:23 to (123) 17:55 now = , 4:58 OPEN CHANNEL W/M OPEN CHANNEL IRRADIANCE. Computed irradiance for the unfiltered Si cell YEAR DAY 4.5 FRSR HEAD TEMPERATURE (99) 23:23 to (123) 17:55 now = , 4:58 Head temperature. During the times of operation, the head temperature was stable at 4C +/ TEMP C Mean= / YEAR DAY

28 ANALYSIS -- OPTICAL DEPTH 3 FRSR 1 MIN SWEEP: , Signal Bin Number One-minute averages of sweep bins during a cloud free morning. Red points are the shadow and edge values used in computing optical depth. Data here are from channel 3, 5 µm. Points on the right side indicate the shadow bins are below the horizon.

29 SHADOW RATIO ANALYSIS -- OPTICAL DEPTH FRSR SHADOW RATIO (99) 23:23 to (123) 17:55 now = , 4: YEAR DAY The shadow ratio 1-min mean and the 1-min standard deviation are used to define cloud free conditions. Red points are worthy of optical depth computation.

30 ANALYSIS -- OPTICAL DEPTH.5 FRSR OPTICAL DEPTH DAILY AVERAGE.45.4 OPTICAL DEPTH (r)41 (m)5 (b)61 (g)66 (c)86 microns JDAY NOON The Langley calibration values determined from this period are used for calculation of optical depth for each day. Colors are red, magenta, blue, green, and cyan. The mean optical depth and standard deviation for the day are shown.

31 ANALYSIS -- PSP IR EFFECTS The PIR thermopile signal is used to derive a PSP correction for IR leakage.

32 ANALYSIS -- PSP IR EFFECT CALVAL SW (blue) & LW (red) (12) : to (124) : now = , 9: YEAR DAY A time series plot of the corrected SW and the LW irradiance during the CalVal exercise.

33 ANALYSIS -- PSP IR EFFECT We compute solar zenith angles and use ze > 9 to define nighttime values. Shown here are the RAD sw values for the PSP. At night the PSP readings generally range from -2 to as much as -1 W/m^2. The plot here shows the nighttime values of the measured short wave irradiance as computed from the RAD.

34 ANALYSIS -- PSP IR EFFECT CORRELATE NIGHTTIME SW AND PIR NIGHTTIME SW 2 NIGHTTIME PIR Following the method described by Michalsky (personal communication) we fit a straight line to the nighttime SW and corresponding PIR thermopile measurement.

35 ANALYSIS -- PSP IR EFFECT (12) : to (124) : now = , 9: The straight line fits was used for all measurements, day or night, to correct the SW measurements. This is the PSP IR correction. The figure here shows the IR offset which is subtracted from the SW measurement.

36 ANALYSIS -- PSP IR EFFECT We show here the raw SW measurements (blue) and the IR corrected SW (red). One still sees about +/-1 W/m^2 variability, but the SW mean at night is very near zero

37 GLOBAL SW IRRADIANCE COMPARE WITH NOAA

38 NOAA(blue) RAD(red) (117) 8:44 to (118) 4:37 now = , 17:37 SW W/m SHORTWAVE COMPARISON We select an almost clear day in order to avoid the minute to minute differences that occur with two instruments with different time constants and different sampling schemes GMT HOUR SW DIFFERENCE, RAD NOAA (117) 5:2 to (118) 8:1 now = , 19:55 (av, stdev, min,max): 4.82, 1.13, 48.48,

39 GLOBAL LW IRRADIANCE COMPARE WITH NOAA

40 LW RAD(blue), NOAA(red) (114) 19:25 to (124) :51 now = , 19:41 IRRADIANCE W/M Mean difference =.41 W/m YEAR DAY

41 RAD TCASE(blue), NOAA TCASE(red) RAD TDOME(blue), NOAA TDOME(red) (12) : to (124) : now = , 15:48 A. B (12) : to (124) : now = , 15:46 TEMPERATURE C TEMPERATURE C YEAR DAY YEAR DAY (117) 8:1 to (118) 8:35 now = , 13:35 A. Tcase, RAD (blu) is several degrees colder than NOAA C. B. Same for Tdome. RAD is colder by several degrees. C. Tcase difference (RAD-NOAA) (blue) and Tdome (red) shows -1 to -5 degc difference. A question is why is the NOAA case and dome temperature so much warmer than the RAD. Possibly the ventilators increase the temperature, especially during daytime, sunny periods

42 TEMPERATURE C TDOME TCASE RAD(blue), NOAA(red) (12) : to (124) : now = , 13:25 DOME-CASE TEMPERATURE DIFFERENCE The RAD Tdome-Tcase shows significant warming during the day when the dome temperature increases dramatically. The NOAA PIR uses a solar shield and thus the Tdome-Tcase temperature difference does not respond to solar insolation. For both instruments the nighttime Tdome is cooler than the case by approximately.5 C YEAR DAY

43 APPLICATION ON A SHIP On the SPIRIT Legs 11 & 12. Optical depth computed from the calibration and from Langleys.

44 APPLICATION ON A SHIP The values of I_ used to compute optical depth. The CAL values are from Thullier 23 and adjusted for solar distances. The LANGLEY values were deduced from the Boulder cal/val in April 213. Filter CAL LANGLEY

45 APPLICATION ON A SHIP The standard FRSR processing programs were applied to data collected on the MAGIC deployment on M/V SPIRIT, Leg12, (magic12). Sunny days were selected. One-minute averages are shown. Blue dots are the OD using the Langley values and red dots are from using the standard ARM calibration

46 ANALYSIS -- DERIVE TOA I_ FROM MFRSR From the NOAA analysis we have time series of A, the atmospheric mass, and the computed top-of-theatmosphere V_t values for each MFRSR channel. We can select cloud free points when 6 < A < 2. For each channel the instantaneous value fo I_t is the corresponding top-of-the-atmosphere measurement for the FRSR. I_t = I * v / V_t where I_t is the TOA measurements for the FRSR head, v is the MFRSR voltage V_t is the TOA value for the MFRSR. The strategy is to compute I_t for each data point and then use a mean value as the calibration value.

47 The solar spectral irradiance from 2 to 24 nm as measured by the solspec spectrometer from the Atlas and Eureca missions (article) Author G. Thuillier and M. Hers\'e and D. Labs and T. Foujols and W. Peetermans and D. Gillotay and P.C. Simon and H. Mandel Journal Solar Physics Year 23 Volume 214 Design, Operation, and Calibration of a Shipboard Fast-Rotating Shadowband Radiometer (article) Author R. Michael Reynolds and Mark A. Miller and Mary Jane Bartholomew Journal \jtec Year 21 Volume 18 Number 2 Pages