Longitude

About: Longitude is a research topic. Over the lifetime, 2260 publications have been published within this topic receiving 54988 citations. The topic is also known as: angle of longitude.

A climatology of the water vapor band brightness temperatures from NOAA operational satellites

Abstract: Measurements of brightness temperature from the water vapor band channels of the National Oceanic and Atmospheric Administration polar satellites from 1981 through 1988 are analyzed. Only clear and cloud-cleared measurements from the operational sounding product are used to produce averages for bins of 2.5° latitude by 2.5° longitude and 5 days. The standard deviations of random errors for these bins are estimated. A unique feature of this dataset is its ability to identify the dry regions in the middle and upper troposphere with unprecedented detail. Results agree with the known climatology in the tropics.

Intra-annual variability of the low-latitude ionosphere due to nonmigrating tides

Abstract: [1] In-situ plasma density measurements from the CHAMP satellite between about 350–420 km altitude are used to delineate intra-annual variations in the longitudinal structure of the F-region ionosphere. It is shown that the longitude structures during mid-day local times are dominated by the space-based longitudinal wavenumbers ks = 2, 4 and 3 in January, July and December, respectively. These conform to the same dominating ks-values characterizing solar thermal tide zonal winds in the dynamo region, namely the westward-propagating semidiurnal tide with planetary-fixed zonal wavenumber s = 4 (SW4), and the eastward-propagating diurnal tides with s = −3 (DE3) and s = −2 (DE2), respectively. DE3 is the dominating tide during the other months. The results presented indicate that nonmigrating tides other than DE3 may significantly impact the longitudinal structure of the low-latitude ionosphere during certain months.

The Pressure, Density, and Temperature of the Earth's Atmosphere to 160 Kilometers

Abstract: A program of pressure measurements with rockets over White Sands, New Mexico, and over the equator has given values for atmospheric pressure, density, and temperature from the ground up to 160 km above sea level. The data have been obtained from about a dozen rocket flights at White Sands, New Mexico, latitude 32° north, longitude 106° west; and from one flight at the equator, longitude 160° west. Measurements were made in every month except April, June, and July. One rocket was flown at midnight, while the others were between 09h 00m and 19h 00m local time. Except for one daytime flight at White Sands, all the pressure data agree within the experimental errors. The fundamental data are pressures measured on the nose tips, nose cones, and tail sections of V-2, Viking, and Aerobee rockets. From these measurements, atmospheric pressures, densities, and temperatures have been deduced. The pressure at 160 km is 2×10−6 mm of Hg, and the density is 1.5×10−6 gm/m3. The temperature reaches a maximum of 270°K at 50 km, a minimum of 190°K at 80 km, and increases to about 500°K at 160 km.

Upper atmosphere of Mars up to 120 km: Mars Global Surveyor accelerometer data analysis with the LMD general circulation model

Abstract: [1] Mars Global Surveyor (MGS) aerobraking accelerometer density measurements are analyzed with the use of the general circulation model (GCM) at the Laboratoire de Meteorologie Dynamique (LMD). MGS constant altitude density data are used, obtaining longitudinal wavelike structures at fixed local times which appear to be dominated by low zonal wave number harmonics. Comparisons with simulated data for different seasons and latitudinal bands at constant altitude are performed. Excellent agreement is obtained between the simulated and observational data for low latitudes, with accuracy in both mean and zonal structure. Higher latitudes show a reduction in agreement between GCM results and MGS data. Comparisons that result in good agreement with the observational data allow for the study of wave composition in the MGS data. In particular, the excellent agreement between the simulations and the data obtained at 115 km during areocentric longitude Ls ≈ 65° allows the extraction of the major contributors to the signature, with the eastward propagating diurnal waves of wave numbers one to three being the major players. Significant contributions are also obtained for eastward propagating semidiurnal waves of wave numbers two, three, and five and diurnal wave number five. A sensitivity study is performed to delineate the effects of the near-IR tidal forcing of the upper atmosphere on the wave content at those heights. Simulations without this forcing yield reduced amplitudes for diurnal eastward propagating waves two and three along with a more latitudinally symmetric response for these two components as well as for diurnal eastward propagating wave number one.