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Nathan Paldor, Yona Dvorkin, Arthur J. Mariano, Tamay Özgökmen, and Edward H. Ryan

1. Introduction In this work we develop a method for reconstructing observed trajectories of near-surface drifters in the Pacific Ocean by incorporating climatological currents with real-time winds. Accurate prediction of (near) surface particle trajectories, in the ocean, is of paramount importance for a number of operational activities, such as search and rescue and monitoring the spread of pollutants. Prediction of particle trajectories is extremely difficult because the uncertainties in our

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Ralph F. Milliff, Jan Morzel, Dudley B. Chelton, and Michael H. Freilich

surface wind datasets are referred to as QSCAT only, National Centers for Environmental Prediction (NCEP) Reanalysis, blended QSCAT+NCEP, Oregon State University (OSU)–NCEP–FNL–no rain, and OSU–NCEP– FNL–rain, where FNL refers to the NCEP operational forecast model surface wind analyses. a. QSCAT only The QSCAT-only winds derive from the QuikSCAT spaceborne scatterometer mission launched in June 1999. QSCAT data processing began in July 1999, and the system continues to operate well. The scatterometer

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Paolo Di Girolamo, Donato Summa, and Rossella Ferretti

periods (IOPs) and 25 days. The main goal of LAUNCH 2005 was the assessment of the impact of variational data assimilation into an operational high-resolution weather forecasting model from a network of ground-based water vapor lidars in comparison to microwave profilers. Figure 4 illustrates the time evolution of the water vapor mixing ratio over a period of ∼32 h from 1805 UTC 1 October to 0215 UTC 3 October 2005. Measurements were stopped shortly afterward because of the onset of thick clouds and

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Jessica L. Proud, Kelvin K. Droegemeier, Vincent T. Wood, and Rodger A. Brown

: Geometrical connections between eigenvectors and the core region of atmospheric vortices. J. Atmos. Sci. , 62 , 4028 – 4042 . Kain, J. S. , and Coauthors , 2009 : Some practical considerations regarding horizontal resolution in the first generation of operational convection-allowing NWP. Wea. Forecasting , 23 , 931 – 952 . Kong, F. , and Coauthors , 2007 : Preliminary analysis on the real-time storm-scale ensemble forecasts produced as a part of the NOAA hazardous weather testbed 2007

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Jeffrey A. Nystuen and Harry D. Selsor

Abstract

Weather observations are needed in remote oceanic regions to support numerical weather forecast models, to provide surface truth for satellite sensors, and to help understand global weather patterns. An acoustic mini-drifting buoy using no moving parts has been designed to meet operational naval demands for real-time monitoring of upper-ocean air–sea interface processes. This buoy is an air-deployable, standard sonobuoy-sized buoy that uses an Argos satellite link to transmit data to users. Interpretation of the ambient sound field allows classification of weather into five categories: wind, wind and drizzle, rain, high seas, and shipping contaminated. Quantitative estimates of wind speed are shown to be in agreement with the Special Sensor Microwave/Imager satellite sensor. Rainfall detection is confirmed and rainfall rate quantified using an acoustic rainfall-rate algorithm. Atmospheric pressure, air and sea temperature, and ambient sound levels are measured directly.

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Xichen Li, Jiang Zhu, Yiguo Xiao, and Ruiwen Wang

), Eq. (8) (cost ∼ k 3 ), and Eq. (5) (cost ∼ k 2 × n ), successively. The cost of each cycle (each additional observation) can be easily calculate as follows: k × ( k × n + m ) + k 2 × n + k 3 + k 3 + k 2 × n . Note that in most forecast systems, k × n ≫ M and k 2 × n ≫ k 3 , we can conclude that the cost of each cycle ∼ k 2 × n , and the cost of the whole process (adding m observations) ∼ k 2 × n × m . This value can be primarily attributed to the

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Jeffrey A. Nystuen, Marios N. Anagnostou, Emmanouil N. Anagnostou, and Anastasios Papadopoulos

experiment in shallow waters ( Amitai et al. 2004a , b ) indicating a very high S –Ze correlation even from the deepest (2000 m) PAL deployment. The results from ISREX, however, were limited in terms of storm cases examined, which motivated the current study aimed to collect continuous and longer-term acoustic data by deploying in November 2008 two PALs ( Anagnostou et al. 2011 ) at two buoy locations of the Hellenic Center for Marine Research real time operational ocean observation system, named

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P. Jonathan Gero, John A. Dykema, and James G. Anderson

accomplished by space-based high-resolution infrared sounders. The determination of satellite sensor uncertainty during prelaunch calibration cannot be assumed to be valid over the operational lifetime of the instrument. The harsh conditions of spacecraft launch and the low earth orbit environment can lead to secular drifts in instrument physical properties that are manifest as a time-dependent bias in the absolute calibration. Degradation affecting blackbodies, which provide the fundamental radiometric

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Aart Overeem, Hylke de Vries, Hassan Al Sakka, Remko Uijlenhoet, and Hidde Leijnse

Abstract

The Royal Netherlands Meteorological Institute (KNMI) operates two operational dual-polarization C-band weather radars providing 2-D radar rainfall products. Attenuation can result in severe underestimation of rainfall amounts, particularly in convective situations that are known to have high impact on society. In order to improve the radar-based precipitation estimates, two attenuation correction methods are evaluated and compared: 1) Modified Kraemer (MK) method, i.e. Hitschfeld-Bordan where parameters of the power-law Z hk h relation are adjusted such that reflectivities in the entire dataset do not exceed 59 dBZ h and attenuation correction is limited to 10 dB; 2) using two-way path-integrated attenuation computed from the dual-polarization moment specific differential phase K dp (Kdp method). In both cases the open-source Python library wradlib is employed for the actual attenuation correction. A radar voxel only contributes to the computed path-integrated attenuation if its height is below the forecasted freezing level height from the numerical weather prediction model HARMONIE-AROME. The methods are effective in improving hourly and daily quantitative precipitation estimation (QPE), where the Kdp method performs best. The verification against rain gauge data shows that the underestimation diminishes from 55% to 37% for hourly rainfall for the Kdp method when the gauge indicates more than 10 mm of rain in that hour. The improvement for the MK method is less pronounced, with a resulting underestimation of 40%. The stability of the MK method holds a promise for application to data archives from single-polarization radars.

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W. L. Smith Sr, Qi Zhang, M. Shao, and E. Weisz

vapor profiles to improve numerical weather prediction (NWP) model forecasts of intense weather through the quasi-continuous assimilation of the atmospheric sounding data. The goal of this research is to demonstrate that sounding products are useful to weather service agencies for nowcasting and NWP purposes. The “nowcasting” products are produced and made available in near–real time using soundings retrieved by the fusion of direct broadcast operational polar (IASI and CrIS) hyperspectral sounding

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