QUELQUES EXEMPLES D'APPLICATION DES MESURES DE RAYONNEMENT À LA DÉTERMINATION DE L'ÉVAPO-TRANSPIRATION EN CLIMAT TROPICAL     

CH. RIOU 《水文科学杂志》2013,58(2):189-208

ABSTRACT

From data obtained at stations set up in Chad, the Central African Republic and Congo-Brazzaville, stretching from the desert to the equatorial zone, it has been possible to compare measurements of evapotranspiration and of evaporation with results obtained by using the energy-balance method. Several difficulties arise in these comparisons since the scale of the measurements (small evaporating surfaces) is generally different from that of the climatic characteristics on which evaporation is dependent.

After proposing a model to resolve this problem and fitting the empirical coefficients of Penman's formula, the author has applied this formula to some results derived for stations in Congo-Brazzaville; the potential evapotranspiration calculated in this way is in good agreement with water balance data.

At these stations the evapotranspiration energy may be a constant percentage of global short-wave radiation.

Finally, the energy-balance method has been used at Brazzaville to measure the actual evapotranspiration over grass during the dry season. The result is that actual and potential evapotranspiration were found to be closely related.

These results indicate the importance of solar readiation in the field of hydrometeorology.  相似文献   

Dissolution forms in Lac de Gras diamonds and their relationship to the temperature and redox state of kimberlite magma     

Yana?FedortchoukEmail author  Dante?Canil  Jon?A.?Carlson 《Contributions to Mineralogy and Petrology》2005,150(1):54-69

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Diurnal and subdiurnal luni-solar nutations: comparisons and effects     

M. Folgueira  CH. Bizouard  J. Souchay 《Celestial Mechanics and Dynamical Astronomy》2001,81(3):191-217

We present a comparison of the diurnal and subdiurnal terms of the three last theories of rigid Earth's rotation: SMART97, RDAN97 and REN 2000. For a better interpretation of the observations, we characterize their contribution to the polar motion and we estimate the non-rigid effects, which are at the level of a few microarcseconds.  相似文献   

Molecular weight distribution of dissolved organic materials in seawater determined by ultrafiltration: a re-examination     

David J. Carlson  Mary Louise Brann  Timothy H. Mague  Lawrence M. Mayer 《Marine Chemistry》1985,16(2):155-171

Most of the dissolved organic materials (DOM) in coastal Maine, Gulf of Maine, and North Atlantic seawaters had molecular weights (MW), determined by ultrafiltration, less than 1000. Only 34% of the DOM had MW greater than 1000, only 6% had MW greater than 30 000, and only 1% was of MW greater than 100 000. The majority of ultrafilter-derived MW data are consistent with patterns shown here; earlier reports of high-MW DOM in seawater were apparently exaggerated due to procedural and ultrafilter artifacts. It is also shown that most ultrafiltration data do not clearly indicate loss of high-MW DOM during estuarine mixing, and that apparent removal could result from decreased retention as ionic strength increases.  相似文献   

Erratum: "Project ELF electromagnetic compatibility assurance program--A status report"     

Genge  M. Carlson  R. 《Oceanic Engineering, IEEE Journal of》1985,10(1):51-51

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Binding of monomeric organic compounds to marcomolecular dissolved organic matter in seawater     

David J. Carlson  Lawrence M. Mayer  Mary Louise Brann  Timothy H. Mague 《Marine Chemistry》1985,16(2):141-153

Several monomeric organic compounds, including amino acids, sugars, and fatty acids, were found to bind abiologically to dissolved macromolecular materials in particle-free seawater at natural substrate concentrations. The binding primarily occurred in ocean surface waters, at rates slower than in situ biological utilization rates of most of the compounds. Seasonal patterns of binding in Gulf of Maine waters may have been related to seasonal variations in macroalgal exudation of polyphenolic materials. Enhanced reactivity of relatively hydrophobic monomers implicated hydrophobic effects as potentially important in marine organic condensations. The resultant condensates showed high particle reactivity, consistent with low concentrations of dissolved condensed materials in seawater.  相似文献   

Real-time sea-state surveillance with Skywave Radar     

Georges  T. Maresca  J.  Jr. Riley  J. Carlson  C. 《Oceanic Engineering, IEEE Journal of》1983,8(2):97-103

To extract sea-state information from the ionospherically distorted echoes received by a skywave radar, we use a signal-processing strategy that permits real-time decisions about the quality of incoming data. This paper explains the need for an on-line processor and describes some of its engineering details. We use an array processor to quickly compute all the spectra required to display ocean waveheight, as well as some indices of data quality, while the radar interrogates an ocean cell. The results are shown in a test using an experimental radar that mapped waveheight over its North Pacific coverage area. Coverage efficiency was 85 percent, and the radar's waveheight estimates averaged 2ft(0.6 m) higher than those forecast by a numerical model.  相似文献   

First Mass-resolved Measurement of High-Energy Cosmic-Ray Antiprotons     

Bergström D  Boezio M  Carlson P  Francke T  Grinstein S  Khalchukov F  Suffert M  Hof M  Kremer J  Menn W  Simon M  Stephens SA  Ambriola ML  Bellotti R  Cafagna F  Ciacio F  Circella M  De Marzo C  Finetti N  Papini P  Piccardi S  Spillantini P  Bartalucci S  Ricci M  Casolino M  De Pascale MP  Morselli A  Picozza P  Sparvoli R  Bonvicini V  Schiavon P  Vacchi A  Zampa N  Mitchell JW  Ormes JF  Streitmatter RE  Bravar U  Stochaj SJ 《The Astrophysical journal》2000,534(2):L177-L180

We report new results for the cosmic-ray antiproton-to-proton ratio from 3 to 50 GeV at the top of the atmosphere. These results represent the first measurements, on an event-by-event basis, of mass-resolved antiprotons above 18 GeV. The results were obtained with the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas-RICH (Ring-Imaging Cerenkov) counter and a silicon-tungsten imaging calorimeter. The RICH detector was the first ever flown that is capable of identifying charge-one particles at energies above 5 GeV. The spectrometer was flown on 1998 May 28-29 from Fort Sumner, New Mexico. The measured p&d1;/p ratio is in agreement with a pure secondary interstellar production.  相似文献   

Cluster Observes the High-Altitude CUSP Region     

B. Lavraud  H. Rème  M. W. Dunlop  J. -M. Bosqued  I. Dandouras  J. -A. Sauvaud  A. Keiling  T. D. Phan  R. Lundin  P. J. Cargill  C. P. Escoubet  C. W. Carlson  J. P. McFadden  G. K. Parks  E. Moebius  L. M. Kistler  E. Amata  M. -B. Bavassano-Cattaneo  A. Korth  B. Klecker  A. Balogh 《Surveys in Geophysics》2005,26(1-3):135-175

This paper gives an overview of Cluster observations in the high-altitude cusp region of the magnetosphere. The low and mid-altitude cusps have been extensively studied previously with a number of low-altitude satellites, but only little is known about the distant part of the magnetospheric cusps. During the spring-time, the trajectory of the Cluster fleet is well placed for dayside, high-altitude magnetosphere investigations due to its highly eccentric polar orbit. Wide coverage of the region has resulted and, depending on the magnetic dipole tilt and the solar wind conditions, the spacecraft are susceptible to encounter: the plasma mantle, the high-altitude cusp, the dayside magnetosphere (i.e. dayside plasma sheet) and the distant exterior cusp diamagnetic cavity. The spacecraft either exit into the magnetosheath through the dayside magnetopause or through the exterior cusp–magnetosheath interface. This paper is based on Cluster observations made during three high-altitude passes. These were chosen because they occurred during different solar wind conditions and different inter-spacecraft separations. In addition, the dynamic nature of the cusp allowed all the aforementioned regions to be sampled with different order, duration and characteristics. The analysis deals with observations of: (1) both spatial and temporal structures at high-altitudes in the cusp and plasma mantle, (2) signatures of possible steady reconnection, flux transfer events (FTE) and plasma transfer events (PTE), (3) intermittent cold (<100 eV) plasma acceleration associated with both plasma penetration and boundary motions, (4) energetic ions (5–40 keV) in the exterior cusp diamagnetic cavity and (5) the global structure of the exterior cusp and its direct interface with the magnetosheath. The analysis is primarily focused on ion and magnetic field measurements. By use of these recent multi-spacecraft Cluster observations we illustrate the current topics under debate pertaining to the solar wind–magnetosphere interaction, for which this region is known to be of major importance.  相似文献   

Water Vapor Variability in the Tropical Western Pacific from 20-year Radiosonde Data     

Junhong Wang  Harold L. Cole  David J. Carlson 《大气科学进展》2001,18(5):752-766

The 20-year (1976-1995) daily radiosonde data at 17 stations in the tropical western Pacific was ana lyzed. The analysis shows that the atmosphere is more humid in a warmer climate on seasonal, inter-annual and long-term (20-year) time scales, implying a positive water vapor feedback. The vertical structure of the long-term trends in relative humidity (RH) is distinct from that on short-term (seasonal and inter-annual) time scales, suggesting that observed water vapor changes on short time scales could not be considered as a surrogate of long-term climate change. The increasing trend of RH (3%-5%/decade) in the upper troposphere is stronger than that in the lower troposphere (1%-2% / decade). Such vertical structure would amplify positive water vapor feedback in comparison to the common assumption of constant RH changes vertically. The empirical orthogonal function (EOF) analysis of vertical structure of RH variations shows distinct features of the vertical structure of the first three EOFs. The first three EOFs are optimal for repre sentation of water vapor profiles and provide some hints on physical mechanisms responsible for observed humidity variability. Vaisala radiosondes were used at nine stations, and VIZ radiosondes used at other eight stations. The Vaisala data are corrected for temperature-dependence error using the correction scheme developed by NCAR / ATD and Vaisala. The comparison of Vaisala and VIZ data shows that the VIZ-measured RHs after October 1993 have a moist bias of ～ 10% at RHs ＜ 20%. During 1976-1995, several changes in cluding both instruments and reporting practice have been made at Vaisala stations and introduce errors to long-term RH variations.  相似文献