Search Results

You are looking at 1 - 10 of 36,536 items for :

  • Refine by Access: All Content x
Clear All
Jonah V. Steinbuck, Paul L. D. Roberts, Cary D. Troy, Alexander R. Horner-Devine, Fernando Simonet, Alfred H. Uhlman, Jules S. Jaffe, Stephen G. Monismith, and Peter J. S. Franks

distributions and flow structures are limited in temporal and spatial resolution. There remains a need for observations that clarify the role of physical processes in redistributing planktonic organisms at small scales. Our ability to reliably measure fine- to microscale turbulence has continued to develop, using, for example, thermal and shear microstructure profilers ( Oakey 1982 ; Carter and Imberger 1986 ; Kocsis et al. 1999 ), acoustic Doppler velocimeters (ADVs; Voulgaris and Trowbridge 1998

Full access
P. Srinivasulu, P. Yasodha, P. Kamaraj, T. N. Rao, A. Jayaraman, S. N. Reddy, and S. Satyanarayana

1. Introduction In recent years, radar wind profilers (RWPs) operating close to the 1-GHz band have been extensively used for atmospheric research and operational meteorology. It is also referred as the lower-atmospheric wind profiler (LAWP) because it is used to probe the lower part of the atmosphere (up to about 5 km). Many LAWPs have been developed in the recent past by research and commercial groups for meteorological applications, in particular to understand the dynamics of the atmospheric

Full access
Hua Wang, Shipeng Su, Haichuan Tang, Lin Jiao, and Yunbo Li

observed continuously; 2) the equipment is complicated to use and inconvenient; 3) some measurement methods are lossy or less economical, such as the use of radiosondes and sounding rockets. Therefore, it is desirable to find a new remote sensing method to monitor atmospheric ducts, which can continuously observe atmospheric ducts without using sounding equipment. Wind profiler radar (WPR) can measure the wind field, spectral width and volume refractivity ( Tatarski 1961 ), atmospheric refractive index

Full access
Giuseppe Zibordi, Jean-François Berthon, and Davide D’Alimonte

1. Introduction Highly accurate in situ radiometric data are a requirement for ocean color activities like bio-optical modeling, vicarious calibration of sensors in space, and validation of remote sensing products ( McClain et al. 2004 ). The specific radiometric quantity relevant to ocean color applications is the normalized water-leaving radiance determined from the subsurface upwelling radiance. The latter can be derived from in-water radiometric profiles of continuous or multiple fixed

Full access
R. Pinkel, M. A. Goldin, J. A. Smith, O. M. Sun, A. A. Aja, M. N. Bui, and T. Hughen

1. Introduction The Wirewalker (WW) is a vertically profiling instrument package propelled by ocean waves. In its simplest form, it is a means of attaching any internally recording instrument to a wire suspended from the sea surface. The WW’s profiling extends the one-dimensional time series recording of the instrument to a two-dimensional depth–time record. The elements of the WW system include a surface buoy, a wire suspended from the buoy, a weight at the end of the wire, and the profiler

Full access
Sarah T. Gille, Aaron Lombrozo, Janet Sprintall, Gordon Stephenson, and Richard Scarlet

for investigating finescale mixing processes in the upper ∼1000 m of the ocean. One of the challenges in using XCTDs is determining the effective vertical resolution of the data. Figure 1 shows examples of XCTD upper-ocean profiles from the North Pacific (15.5°N, 139°E, 14 March 2001) and Drake Passage (57.03°S, 62.55°W, 5 July 2006). In the North Pacific, temperature and conductivity are highly stratified ( Figs. 1a,b ), whereas in the Drake Passage, temperature and conductivity have low

Full access
Robert Schafer, Susan K. Avery, Kenneth S. Gage, and George N. Kiladis

1. Introduction The sparseness of in situ wind observations over the tropical oceans makes wind profiler observations crucial for understanding weather and climatological processes as well as for validating forecast/analysis/assimilation models. The potential value of profiler data in improving reanalysis products over the central equatorial Pacific was demonstrated by Gage et al. (1988) who showed that the bias between operational analysis and profiler observations was reduced from 1–3 to 0

Full access
A. M. Thurnherr

1. Introduction Eulerian measurements of ocean velocities are used in many different contexts. Examples include transport estimation of oceanic currents, as well as the study of physical oceanographic processes such as mesoscale eddies, internal waves, etc. Acoustic Doppler current profilers (ADCPs) are particularly useful for sampling the oceanic velocity field because they yield velocity profiles, rather than the point samples recorded by traditional current meters. ADCPs obtain velocity

Full access
Christopher R. Williams

1. Introduction Wind profilers operating at 50 MHz are able to simultaneously observe the motion of hydrometeors and the ambient air motion ( Fukao et al. 1985 ). These radars detect backscattered energy from hydrometeors following Rayleigh scattering theory ( Doviak and Zrnic 1993 ; Rogers et al. 1993 ). These radars also detect ambient air motion surrounding the hydrometeors from energy being backscattered by gradients of temperature and humidity following Bragg scattering theory ( Balsley

Full access
Alexander Haefele and Niklaus Kämpfer

1. Introduction Water vapor is the most important natural greenhouse gas of the atmosphere and has a large impact on its radiative properties and hence on its thermodynamic balance. Despite the importance of water vapor in the climate system and weather forecasting, there is no technique available, neither ground-based nor spaceborne, that can provide continuous measurements of the humidity profile under all weather conditions. Ground-based microwave radiometers measuring the pressure

Full access