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Claire Henocq, Jacqueline Boutin, Gilles Reverdin, François Petitcolin, Sabine Arnault, and Philippe Lattes

parameter for the detection via statistical methods of the salinity differences between surface L-band radiometer measurements and in situ measurements resulting from rainfall. However, more than 75% of vertical salinity differences comes from 13 fixed positions in the tropics (TAO/TRITON and PIRATA moorings), mainly located at 95°W. More measurements above 5 m are urgently needed to extend and improve this work. This paper focuses on vertical salinity differences between 1 and 10 m. In the case of a

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Valentin Louf, Alain Protat, Robert A. Warren, Scott M. Collis, David B. Wolff, Surendra Raunyiar, Christian Jakob, and Walter A. Petersen

and 2007, to reduce the data size and to allow real-time transmission to the regional forecasting office, the radar gate range was changed to 300 m, and data were sampled with an azimuthal resolution of 1.5°. Before 2007, the azimuthal indexing had to be corrected while, after 2007, the data are generated with the data synced to the azimuthal sampling. CPOL has produced more than 350 000 plan position indicator scans over 17 wet seasons (November–May). Because of its location in the tropics and

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Peter T. May

exceptionof the work of Weber and Wuertz, the profiler andradiosonde sites have been separated by several tens ofkilometers. The differences in winds were well explained by the spatial separation, usually with referenceto the work of Jasperson (1982) on spatial differencesof simultaneous radiosonde ascents. There has alsobeen comparatively little verification published forprofilers in the tropics [except for 26 days of data fromPuerto Rico where the site separation was around 90 Corresponding author

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Qi Hu, Zhaoning Liang, and Michael W. Hoffman

Agricultural Research Project NEB-40-040. REFERENCES Blade, I. , and Hartmann D. L. , 1993 : Tropical intraseasonal oscillations in a simple nonlinear model. J. Atmos. Sci. , 50 , 2922 – 2939 . 10.1175/1520-0469(1993)050<2922:TIOIAS>2.0.CO;2 Chang, C. P. , 1977 : Viscous internal gravity waves and low-frequency oscillations in the tropics. J. Atmos. Sci. , 34 , 901 – 910 . 10.1175/1520-0469(1977)034<0901:VIGWAL>2.0.CO;2 Chang, C. P. , and Lim H. , 1988 : Kelvin wave-CISK: A possible

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K. S. Gage, J. R. Mcafee, W. L. Ecklund, D. A. Carter, C. R. Williams, P. E. Johnston, and A. C. Riddle

contrasts across thePacific Ocean basin are maximum. Upper-troposphericwesterlies are weakest when the contrasts across thePacific Ocean basin are weakest as they are during thewarm phase of the Southern Oscillation (El Nifio).6. Concluding remarks The Christmas Island wind profiler has operated reliably through most of the first six years since it beganroutine operation in March 1986. It can be viewed asa prototype for VHF wind profilers in the tropics. Indeed, VHF wind profilers have subsequently

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David A. Marks, David B. Wolff, Lawrence D. Carey, and Ali Tokay

Abstract

The dual-polarization weather radar on the Kwajalein Atoll in the Republic of the Marshall Islands (KPOL) is one of the only full-time (24/7) operational S-band dual-polarimetric (DP) radars in the tropics. Through the use of KPOL DP and disdrometer measurements from Kwajalein, quality control (QC) and reflectivity calibration techniques were developed and adapted for use. Data studies in light rain show that KPOL DP measurements are of sufficient quality for these applications. While the methodology for the development of such applications is well documented, the tuning of specific algorithms to the particular regime and observed raindrop size distributions requires a comprehensive testing and adjustment period. Presented are algorithm descriptions and results from five case studies in which QC and absolute reflectivity calibration were performed and assessed. Also described is a unique approach for calibrating the differential reflectivity field when vertically pointing observations are not available. Results show the following: 1) DP-based QC provides superior results compared to the legacy Tropical Rainfall Measuring Mission (TRMM) QC algorithm (based on height and reflectivity thresholds), and 2) absolute reflectivity calibration can be performed using observations of light rain via a published differential phase–based integration technique; results are within ±1 dB compared to independent measurements. Future extension of these algorithms to upgraded Weather Surveillance Radar-1988 Doppler (WSR-88D) polarization diverse radars will benefit National Aeronautics and Space Administration’s (NASA’s) Precipitation Measurement Missions (PMM) validation programs.

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Christopher R. Williams, Warner L. Ecklund, and Kenneth S. Gage

996 JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY VOLUME I2Classification of Precipitating Clouds in the Tropics Using 915-MHz Wind Profilers CHRISTOPHER R. WILLIAMS AND WARNER L. ECKLUNDCooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado. Boulder, Colorado KENNETH S. GAGENOA.4.4eronomy Laboratory, Boulder, Colorado(Manuscript received 12 August 1994

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I. Hoteit, B. Cornuelle, V. Thierry, and D. Stammer

adjustments. Finally, the comparison between the experiments NCEPF and NCEPW, which are forced with different heat and freshwater fluxes but identical wind stress, will be used to assess the effects of the thermohaline forcing. The ECCO adjustments increase the (1992–2000 time) mean easterly wind stress in the tropical Pacific while making much smaller changes in the meridional wind component ( Fig. 1 ). This agrees with Josey et al. (2002) , who reported that NCEP wind stress in the tropics was weak

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T. T. Wilheit, P. V. Hobbs, K. Jin, A. L. Rangno, M. E. Triesky, and J. R. Wang

concerned, is difficult. Most of the Tropics are ocean covered with the attendant logistical difficulties in making conventional rainfall measurements. Land areas have their own set of difficulties. The only practical approach to measure rainfall throughout the Tropics is to use satellite-based measurements. Passive microwave measurements have many advantages for this measurement and are applied on the Tropical Rainfall Measuring Mission (TRMM) satellite via the TRMM Microwave Imager (TMI) and on the

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Jared W. Marquis, Alec S. Bogdanoff, James R. Campbell, James A. Cummings, Douglas L. Westphal, Nathaniel J. Smith, and Jianglong Zhang

lower QL = 1 data experienced OTC contamination at approximately 36%. This results in an overall QA dataset OTC contamination rate of ~26% throughout the tropics. Table 1. Collocated data counts—all-cloud, all-cirrus, and OTC contamination statistics—calculated from Aqua -MODIS/CALIOP collocation globally and for the Atlantic, Indian, and Pacific Ocean basins. Quality control refers to the MODIS QL = 0 and QL = 1 Level 2 datasets used for collocation with CALIOP. OTC COD occurrence histograms for

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