Lei Shi NOAA National Climatic Data Center Asheville, NC, U.S.A. Inter-satellite differences of HIRS longwave channels derived from global observation Lei Shi NOAA National Climatic Data Center Asheville, NC, U.S.A.
Datasets HIRS channels 1-12 Two pairs of satellites NOAA-14 and NOAA-15 (transition from HIRS/2 to HIRS/3) NOAA-17 and METOP-A (transition from HIRS/3 to HIRS/4) Two sources of overlapping data Short-term global SNO Julian Days 102-129 in 2003 for NOAA-14 and NOAA-15 pair Julian Days 66-185 in 2009 for NOAA-17 and METOP-A pair Multi-year polar SNO 1999-2003 for NOAA-14 and NOAA-15 pair 2008-2011 for NOAA-17 and METOP-A pair 30 years
M02 Credit: Hai-Tien Lee, http://www1.ncdc.noaa.gov/pub/data/sds/cdr/docs/hirs-olr-catbd.pdf
NOAA-14 and NOAA-15
NOAA-17 and METOP-A
Atmospheric Transmission Spectrum
N14-N15 Channel 4
N17-M02 Channel 4
N14-N15 Diff as function of Tb
N17-M02 Diff as function of Tb
N14-N15 Diff as function of lapse rate
N17-M02 Diff as function of lapse rate
N14-N15 Channel LRF ISD Mean LRF Mean ISD STD LRF STD Correlation Channel LRF ISD Mean LRF Mean ISD STD LRF STD Correlation Short-term Global 1 CH2-CH1 -1.74 -10.45 1.85 2.90 -0.243 2 CH3-CH2 -0.85 -0.26 0.42 0.87 -0.228 3 CH4-CH3 -0.10 13.86 0.31 4.90 0.391 4 CH5-CH4 4.02 12.56 1.14 2.61 0.963 5 CH6-CH5 0.79 12.78 0.26 2.42 0.754 6 CH7-CH6 0.51 13.16 2.70 0.297 7 CH8-CH7 2.50 16.65 0.67 4.45 0.795 Multi-year Polar -1.22 -7.90 1.10 4.82 0.361 -0.54 -0.42 0.62 2.78 0.411 -0.32 4.95 0.47 5.77 0.563 1.45 5.27 1.08 2.48 0.830 0.21 4.60 0.40 3.09 0.412 0.24 3.67 0.30 3.53 0.351 0.57 3.03 0.73 3.87 0.839 All -1.49 -9.17 1.89 0.098 -0.73 -0.27 1.15 -0.007 -0.12 11.72 0.33 6.87 0.305 3.39 10.66 1.78 0.976 0.66 10.85 0.39 4.92 0.870 0.45 11.19 5.21 0.495 2.11 13.98 7.40 0.922
N17-M02 Channel LRF ISD Mean LRF Mean ISD STD LRF STD Correlation Channel LRF ISD Mean LRF Mean ISD STD LRF STD Correlation Short-term Global 1 CH2-CH1 -1.79 -11.58 3.67 5.38 -0.606 2 CH3-CH2 -0.83 0.27 0.65 1.32 -0.114 3 CH4-CH3 0.10 8.90 0.51 4.23 0.393 4 CH5-CH4 1.29 14.38 0.61 5.12 0.900 5 CH6-CH5 -0.60 11.43 0.34 4.02 -0.813 6 CH7-CH6 -0.10 9.85 0.30 -0.567 7 CH8-CH7 -0.33 17.20 0.36 8.13 -0.370 Multi-year Polar -2.18 -9.39 4.13 6.73 -0.461 -0.59 -1.01 0.73 3.23 0.115 -0.41 1.63 0.85 4.64 0.744 0.35 5.99 0.49 3.61 0.747 -0.20 4.18 0.32 3.28 -0.527 0.22 3.32 0.37 3.21 -0.414 -0.05 4.08 0.48 4.76 -0.389 All -1.92 -10.83 3.84 5.96 -0.544 -0.75 -0.17 0.69 2.25 -0.029 -0.07 6.42 5.56 0.621 0.97 11.52 6.13 0.917 -0.47 8.96 0.38 5.11 -0.805 0.01 7.62 4.87 -0.623 -0.23 12.72 0.42 9.48 -0.457
Linear regression for CH4 inter-satellite difference ISDN14-N15 = 0.400 x ΔTbCH5-CH4 – 0.993 ISDN17-M02 = 0.109 x ΔTbCH5-CH4 – 0.287
Conclusions The multi-year polar SNO generally provides larger observation ranges of brightness temperatures in channels 1-4. The global SNO extends the brightness temperature observations to the warm sides for channels 5-12, and captures the occurrences of larger inter-satellite differences for most HIRS longwave channels. For HIRS channel 4, the inter-satellite differences are the largest in low latitudes where both lapse rate and Tb are large. The difference in inter-satellite difference patterns in low latitudes and high latitudes produces a fork feature in channel-4 Tb scatter plots between overlapping satellites.