Search results for "sonde"
showing 10 items of 64 documents
Consistency between GRUAN sondes, LBLRTM and IASI
2017
Abstract. Radiosonde soundings from the GCOS Reference Upper-Air Network (GRUAN) data record are shown to be consistent with Infrared Atmospheric Sounding Instrument (IASI)-measured radiances via LBLRTM (Line-By-Line Radiative Transfer Model) in the part of the spectrum that is mostly affected by water vapour absorption in the upper troposphere (from 700 hPa up). This result is key for climate data records, since GRUAN, IASI and LBLRTM constitute reference measurements or a reference radiative transfer model in each of their fields. This is specially the case for night-time radiosonde measurements. Although the sample size is small (16 cases), daytime GRUAN radiosonde measurements seem to h…
Balloon-borne match measurements of midlatitude cirrus clouds
2014
Observations of high supersaturations with respect to ice inside cirrus clouds with high ice water content (> 0.01 g kg−1) and high crystal number densities (> 1 cm−3) are challenging our understanding of cloud microphysics and of climate feedback processes in the upper troposphere. However, single measurements of a cloudy air mass provide only a snapshot from which the persistence of ice supersaturation cannot be judged. We introduce here the "cirrus match technique" to obtain information about the evolution of clouds and their saturation ratio. The aim of these coordinated balloon soundings is to analyze the same air mass twice. To this end the standard radiosonde equipment is complemente…
Summertime columnar content of atmospheric water vapor from ground-based Sun-sky radiometer measurements through a new in situ procedure
2010
[1] A new in situ technique for the retrieval of atmospheric water vapor content (i.e., precipitable water content) from Sun photometric direct solar irradiance measurements, taken at the 940 nm wavelength during clear‐sky conditions, is presented. The procedure is applied to summer data recorded in 2007, 2008, and 2009 with a Sun‐sky radiometer at the San Pietro Capofiume station in the Po valley, Italy. It is a preliminary development of the retrieval procedure providing the columnar water vapor content from measurements performed with PREDE Sun‐sky radiometers. The technique brings improvement and innovation by retrieving the best values of constants (a and b), characterizing atmospheric…
Synoptic-scale variability of the polar and subpolar tropopause: Data analysis and idealized PV inversions
2002
The synoptic-scale variability of the polar and subpolar tropopause is investigated based on radiosonde and European Centre for Medium-Range Weather Forecasts Reanalysis data in combination with idealized potential vorticity (PV) inversions. A regression analysis is performed to examine the relationship between the relative vorticity at tropopause level, the tropopause displacement, the static stability above the tropopause, and the anomalies of tropopause temperature and potential temperature. The results are compared with regression coefficients computed from a large number of PV inversions. Generally, a cyclonically influenced tropopause is lower, warmer and potentially colder than avera…
The impact of a mesoscale convective system cold pool on the northward propagation of the intertropical discontinuity over West Africa
2009
The interaction between a mesoscale convection system cold pool and the intertropical discontinuity (ITD) is investigated on two consecutive days (5 and 6 June 2006), in the framework of the African Monsoon Multidisciplinary Analysis Special Observing Period (SOP 1a). Satellite imagery and surface meteorological observations are used to track the movement of the ITD prior to and after its interaction with the cold pool. The impact of the northward propagating cold pool on the Sahelo-Saharan planetary boundary layer (PBL) thermodynamics and aerosol vertical distribution is analyzed by means of airborne and ground-based measurements over the two-day period. Complementary European Centre for M…
Trends in column integrated water vapour over Europe from 1973 to 2003
2010
The spatial and temporal variations of atmospheric precipitable water (PW) content anomalies were analysed over Europe from 1973 to 2003 using daily data (0000 and 1200 UTC) from National Center of Environmental Prediction and National Center of Atmospheric Research Reanalysis project (NCEP-1) and in situ radiosonde data. Mann–Kendall trend tests were applied to long-term PW time series. Technology changes influence PW radiosonde trends, although these are in agreement with NCEP-1 trends. Over the south of the Iberian Peninsula, trends are negative and statistically significant ( 0.04 mm year−1; p < 0.05). Seasonal trends revealed negative and significant trends over the Iberian Peninsula f…
Validation of Landsat-7/ETM+ Thermal-Band Calibration and Atmospheric Correction With Ground-Based Measurements
2010
Ground-based measurements of land-surface temperature (LST) performed in a homogeneous site of rice crops close to Valencia, Spain, were used for the validation of the calibration and the atmospheric correction of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) thermal band. Atmospheric radiosondes were launched at the test site around the satellite overpasses. Field-emissivity measurements of the near-full-vegetated rice crops were also performed. Seven concurrences of Landsat-7 and ground data were obtained in July and August 2004-2007. The ground measurements were used with the MODTRAN-4 radiative transfer model to simulate at-sensor radiances and brightness temperatures, which were c…
Comparison of Radiosonde and Remote Sensing Data to Evaluate Convective Forest Fire Risk: The Haines Index
2018
Haines Index (HI) has been associated with convective forest fires risk. Temperatures and humidities in low atmospheric levels are required to compute HI and usually, atmospheric sounding data are used for this purpose. However, spatial and temporal resolutions of these data are coarse and remote sensing data could improve them. Therefore, the aim of this work is to test remote sensing data from the Atmospheric Infrared Sounder (AIRS) instrument on board the EOS Aqua satellite, specifically the Level 2 V6 products (AIRX2RET and AIRS2RET), for this purpose. First, we validated the remote sensing data with radiosonde daytime and nighttime data located in the Iberian Peninsula in 2014. Signifi…
Política en la televisión del Futuro. De la gran plataforma de la macrotelevisión a la búsqueda de las microaudiencias
1994
Intervención de Vidal-Beneyto en el Seminario "Televisión y Política". Cuenca, 13 y 14 diciembre 1993.
Convezione Naturale in un Canale Verticale Riscaldato: un algoritmo per la gestione automatica mediante LabView della movimentazione della sonda anem…
2002
Si è progettato e realizzato un sistema semiautomatico per acquisizione dati finalizzato allo studio della convezione naturale in un canale verticale riscaldato, applicabile ad un’apparecchiatura sperimentale già esistente in un laboratorio del Dipartimento di Ricerche Energetiche ed Ambientali (DREAM). Tale sistema si è reso necessario in quanto detta apparecchiatura sperimentale era corredata da una serie di strumenti risalenti ad una configurazione in buona parte datata, e che quindi presentava molti limiti. In particolare essa utilizzava un vecchio linguaggio Basic HP ormai del tutto abbandonato, e pertanto non suscettibile di implementazione. Per di più non è compatibile con gli attual…