London\2007 \KSK15S\CR3000\ Corrected RawData\ Radiation

UVA, UVB & Quantum Data Correction This document explains the conversion of all previous UVA, UVB and Quantum data due to an error in the application of the zero offset. Table 1. UVA, UVB and Quantum applied calibration constants and offsets since measurement began (DOY170). DOY Date & Time CR3000 Program Variable Multiplier (mV) Calibration Constant Zero Offset 1701 19/06/07 08:45 LondonRoof2006_V3.CR3 UVA 1000 1.0 -0.03 UVB 1000 1.0 0.14 Quantum 5000 1.0 0.08 1722 21/06/07 LondonRoof2006_V3_3.CR3 UVA 1000 48.03 (mV/W m-2) -0.03 UVB 1000 66.773 (mV/W m-2) 0.14 Quantum 5000 1.667 (mV/ μmol m-2 s-1) 0.08 1834 02/07/07 LondonRoof2006_V3_4.CR3 UVA 5000 48.03 (mV/W m-2) -0.03 UVB 5000 66.773 (mV/W m-2) 0.14 Quantum 5000 1.667 (mV/ μmol m-2 s-1) 0.08 183 02/07/07 LondonRoof2006_V3_5.CR3 UVA 5000 4.8035 (mV/W m-2) -0.03 UVB 5000 66.773 (mV/W m-2) 0.14 Quantum 5000 1.667 (mV/ μmol m-2 s-1) 0.08 190 09/07/07 LondonRoof2006_V3_6.CR3 UVA 5000 0.02082 (mV/W m-2) -0.03 UVB 5000 0.014755 (mV/W m-2) 0.14 Quantum 5000 0.6 (mV/ μmol m-2 s-1) 0.08 2066 25/07/07 LondonRoof2006_V3_7.CR3 UVA (W m-2) 5000 0.02082 (mV/W m-2) -0.03 UVB (W m-2) 1000 0.014755 (mV/W m-2) 0.14 Quantum (μmol…) 5000 0.6 (mV/ μmol m-2 s-1) 0.08 UVA (μmol…) 5000 0.059666 (mV/ μmol m-2 s-1) -0.03 UVB (μmol…) 1000 0.036523 (mV/ μmol m-2 s-1) 0.14 Quantum (W m-2) 5000 0.11926 (mV/W m-2) 0.08 Notes 1) Program only run briefly. 2) LondonRoof2006_V3_2.CR3 was never installed onto the data logger. Reported values are in different units. 3) This value is incorrect actual value from calibration sheet should be 67.77 mV per W m-2. 4) LondonRoof2006_V3_4.CR3 was tested during the day and was found to have incorrect multipliers so was replaced with LondonRoof2006_V3_5.CR3. This explains missing data from DOY 183. 5) Multiplier for UVA set to 4.803 (previously 48.03) to obtain reasonable values for further analysis. 6) UVA, UVB and Quantum calculated in both μmol m-2 s-1 and W m-2 from output voltages. The standard deviation in μmol m-2 s-1 is also determined. Data Correction The pre-DOY 206 data were back converted to the raw voltage outputs (mV). The data is saved in the CR3000 data format (RFYYDDD.dat) files. The data files are located on the LondonRawData drive at S:\KCLroof\2007\CR3000\Corrected. The corrected voltage data were then used to calculate the UVA, UVB and Quantum (in both W m-2 and μmol m-2 s-1) using first the zero offsets and then the calibration constants as listed in Table 1 for DOY 206. These calculations are stored in the combined radiation and WXT510 data files (LRYYYYDDD_15.txt). The old uncorrected data is located in the uncorrected folder found in each monthly folder at S:\KCLroof\2007\WXT510 (LondonRawData). Data post-DOY 206 (UVA, UVB and PAR already calculated in both W m-2 and μmol m-2 s-1) were converted back into raw output voltages before the offset and calibration constants were applied using the values presented in Table 1 for DOY 206. This data is stored in both the CR3000 and combined data formats in the previously mention file locations on LondonRawData. Final Word Data was corrected between DOY 172 and DOY 220 (16:30). After this time a new CR3000 program was installed to correct the above problems.