Search Results

You are looking at 141 - 150 of 215 items for :

  • Acoustic measurements/effects x
  • Monthly Weather Review x
  • Refine by Access: All Content x
Clear All
Steven C. Sherwood and Ralph Wahrlich

as observed during the Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean–Atmosphere Response Experiment (COARE), including further discussion of convective organization. The source of such forms of organization must lie in the interaction between convection and environmental state variables, so a key to understanding them is to learn how convective effects below a given length scale respond to the environmental variables averaged over that scale. If this is understood quantitatively on

Full access
Ioana Colfescu, Joseph B. Klemp, Massimo A. Bollasina, Stephen D. Mobbs, and Ralph R. Burton

Snæfellsnes Peninsula focused primarily on surface wind characteristics, this work makes use of a unique set of aircraft measurements obtained on 20 October 2016 to analyze the dynamics of these observed lee waves. The observations are complemented by a set of simulations with the regional Weather Research and Forecasting (WRF) Model as well as by idealized 2D and 3D simulations and linear analytic analyses to document the dynamics that govern the observed wave structure and its generation mechanisms by

Open access
Youngsun Jung, Ming Xue, and Guifu Zhang

parameters compensate each other in terms of the observed radar reflectivity, causing solution nonuniqueness. This result suggests that additional constraints provided by polarimetric radar measurements may help improve the well posedness of the problem ( Jung et al. 2008a , b , hereinafter JZX08 and JXZS08 , respectively). JXZS08 showed the positive impacts of directly assimilating simulated polarimetric variables on state estimation in a perfect-model scenario. In this paper, extending the earlier

Full access
John W. Nielsen-Gammon, Xiao-Ming Hu, Fuqing Zhang, and Jonathan E. Pleim

United States the rawinsonde launch times are not at the times of maximum sensitivity. The efficacy of assimilating rawinsonde data to adjust parameters may be largely confined to effects caused by mixing ratio observations, since mixing ratio sensitivities are relatively uniform throughout the diurnal cycle. Unlike rawinsonde observations, radar wind profiler observations are effectively continuous and, when coupled with the Radio-Acoustic Sounding Systems (RASS), provide virtual temperature

Full access
Christina Holt, Istvan Szunyogh, Gyorgyi Gyarmati, S. Mark Leidner, and Ross N. Hoffman

errors can have catastrophic analysis and forecast impacts, especially if the specified observation errors are small. Therefore, finding a proper mix of the measures to make the data assimilation system robust to model errors requires careful considerations and numerical experimentation, because even highly accurate observations can create unbalanced analyses and excite adjustment processes with negative effects on forecast quality. In this study, we search for efficient methods for the assimilation

Full access
C. E. Dorman and C. D. Winant

side of the Santa Barbara airport, 2 km from the ocean. The radar profiler provided hourly vertical profiles of horizontal winds at 100 m vertical spacing. Hourly, consensus-averaged winds, which are used here, were calculated from measurements made every few minutes with some limited intervals of interference from birds removed. Vertical profiles of a virtual temperature, assumed to be the air temperature, were constructed from a radio acoustic sounding system that is operated in conjunction with

Full access
S. K. Deb, C. M. Kishtawal, P. K. Pal, and P. C. Joshi

some studies have reported the use of microwave satellite measurements for the prediction of intensity of tropical cyclones ( Kidder et al. 2000 ; Wentz et al. 2000 ). The purpose of the present study is to examine the impact of SST derived from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) on the simulation of the severe rainfall event of 26 July 2005 over Mumbai, using the Brazilian Regional Atmospheric Modeling System (BRAMS) and the Advanced Research Weather Research

Full access
Christian L. Keppenne, Michele M. Rienecker, Jossy P. Jacob, and Robin Kovach

more biased than the other EnKF experiments. About 200 independent acoustic Doppler current profiler (ADCP) measurements are available along the equator at 156°E, 170°W, and 140°W for December 2001. Figure 11e is obtained by bilinear interpolation between the monthly-mean measurements at all data points. Figures 11a–d show equatorial Pacific u sections from ocean restart files on 31 December 2001 in the control, TOI, EnKF-17, and EnKF-65. With the double caveat that Figs. 11a–d do not show

Full access
Robin L. Tanamachi, Louis J. Wicker, David C. Dowell, Howard B. Bluestein, Daniel T. Dawson II, and Ming Xue

1. Introduction Radar is one of few atmospheric measurement tools capable of collecting volumetric data resolving substorm-scale features. Assimilation of radar data into numerical weather prediction (NWP) models to improve understanding of convective storm dynamics is now a fairly routine exercise, and analysis and prediction of high-impact, substorm-scale features such as tornadoes is a natural objective. Numerous studies have been undertaken in this area in the past two decades; summaries of

Full access
Claudia C. Stephan, M. Joan Alexander, Michael Hedlin, Catherine D. de Groot-Hedlin, and Lars Hoffmann

1. Introduction The Earthscope USArray Transportable Array (TA) is a network of approximately 400 seismo-acoustic stations deployed on a 70-km Cartesian grid covering an area of 2 000 000 km 2 in the continental United States ( Busby et al. 2006 ). The network moved eastward through station redeployments between 2004 and 2013, has since left the lower 48 states and is being redeployed in Alaska. Although the array was originally designed for seismological studies, in 2009 an atmospheric sensor

Full access