TOVS Path-P

• Path-P is a derivative of Path-B with polar modifications

• Processed north of 60 N, 1979-2004, 100 km grid, daily, monthly

• Temperature and humidity profiles, cloud fraction, cloud height

Axel SchweigerPolar Science Center

University of Washington

(Given by Jeff Key, NOAA/NESDIS, Madison)

Current Path-P Activities• Compilation of Collocation Data Set (1979-2004)

– Radiosondes (multiple data sets)– EECRA (surface cloud observations, 1979-1996)– Lidar/Radar cloud obs. from (SHEBA, Barrow, SGP)– Snow and Ice Charts (NSIDC) – HIRS/MSU (Brightness Temperatures)– Area N40 + SGP, possible future expansion

• Rework of cloud algorithm– Adjustment of thresholds, validation– Additional tests (e.g. 7.2 -11 μm after Liu et. al. )

• Recomputation of Radiance Bias Adjustments• Eventual reprocessing• Will allow point by point comparison of surface cloud observations

with HIRS/MSU-derived.

TPP and APP-X

WinterDJF

SpringMAM

-4 %/dec -7%/dec

+5%/dec +4%/dec

1980 2001 1980 2001

TPP and APP-X 1980-2001 (1982-1999)

SummerJJA

FallSON

1980 2001 1980 2001

APP-X vs. TOVS Path-P: JJA, Beaufort Sea

AP

P-X

TOVS Path-P (From J. Francis)

ERA-40 Winter (DJF) Total Cloud Fraction (1980-2001)

Trend

%/decade

57 01

12%/decade

ERA-40 and TPP Cloud Fraction Spring (MAM)

ISCCP D1 TOVS Path-P

Summer

Winter

ISCCP D1 Clear Sky Composite vs Surface Obs