Spectrally resolved observations of atmospheric emitted radiance in the H2O rotation band

This paper presents the project Earth Cooling by Water Vapor Radiation, an observational programme, which aims at developing a database of spectrally resolved far infrared observations, in atmospheric dry conditions, in order to validate radiative transfer models and test the quality of water vapor continuum and line parameters. The project provides the very first set of far-infrared spectral downwelling radiance measurements, in dry atmospheric conditions, which are complemented with Raman Lidar-derived temperature and water vapor profiles

Lidar and radar measurements of the melting layer in the frame of the Convective and Orographically-induced Precipitation Study: observations of dark and bright band phenomena

During the Convective and Orographically-induced Precipitation Study (COPS), lidar dark and bright bands were observed by the University of BASILicata Raman lidar system (BASIL) during several intensive (IOPs) and special (SOPs) observation periods (among others, 23 July, 15 August, and 17 August 2007). Lidar data were supported by measurements from the University of Hamburg cloud radar MIRA 36 (36 GHz), the University of Hamburg dual-polarization micro rain radars (24.1 GHz) and the University of Manchester UHF wind profiler (1.29 GHz). Results from BASIL and the radars for 23 July 2007 are illustrated and discussed to support the comprehension of the microphysical and scattering processes responsible for the appearance of the lidar and radar dark and bright bands. Simulations of the lidar dark and bright band based on the application of concentric/eccentric sphere Lorentz-Mie codes and a melting layer model are also provided. Lidar and radar measurements and model results are also compared with measurements from a disdrometer on ground and a two-dimensional cloud (2DC) probe on-board the ATR42 SAFIRE

Lidar and Radar Measuements of the melting layer in the frame of the Convective and Orographically-induced Precipitation Study

During the Convective and Orographically-induced Precipitation Study (COPS), lidar dark/ bright and bands were observed by the Univ. of BASILicata Raman lidar system (BASIL) on several IOPs and SOPs (among others, 23 July, 15 August, 17 August). Dark/bright band signatures appear in the lidar measurements of the particle backscattering. Lidar data are supported by measurements from the University of Hamburg cloud radar MIRA 36 (36 GHz), the University of Hamburg dual-polarization micro rain radars (24.1 GHz) and the University of Manchester Radio UHF clear air wind profiler (1.29 GHz). Results from BASIL and the radars will be illustrated and discussed at the Conference to support in the comprehension of the microphysical and scattering processes responsible for the appearance of the lidar dark band and radar bright band

ECOWAR/COBRA: A Research Contribution to Spectrally Resolved Observations of the Earth Emission Spectrum in the Water Vapour Rotation Band (17-50 micron) to Test Models of Atmospheric Radiative Transfer

There is a growing interest in the far infrared spectral region (17 to 50 micron) of the Earth emission spectrum, since this portion of the spectrum contains the characteristic, and fundamental, molecular rotational band for water vapour. Water vapour is, indeed, the main greenhouse gas in the atmosphere and it plays an important role in the mean and upper troposphere influencing the Earth radiative energy balance. Spectrally resolved observations and knowledge of radiative transfer for clear and cloudy skies in the water vapour rotational band are important to test climate models and ultimately resolve some of the contentious arguments about global change. The relevance to the Earth energy budget of the spectral region 17 to 50 micron has been put forward by many authors. Nevertheless, a) the spectral absorption properties of water vapour, in addition to its vertical distribution, have received very poor attention, and b) the far-infrared portion of the atmospheric emission spectrum has been largely unexplored and very few measurements have been made in the past. Nowadays, it is largely recognized that the lack of validation of far infrared model continuum and line parameters under atmospheric conditions is hampering a substantial progress in our ability to correctly parameterize water vapour optical properties in climate models. The ECOWAR (Earth COoling by WAter vapouR emission) or COBRA (an Italian acronym for analysis of the water vapour continuum absorption in the H2O rotational band) project is an experimental field campaign that contributes to bridge the knowledge gap about optical properties of water vapour in the far infrared through an observational programme. This work will review the status of ECOWAR/COBRA and its results at the end of the main steps of the programme (campaign in January 2007 and in March 2007). ECOWAR/COBRA is a co-ordinated project among four University research teams ( University of Bologna , Potenza and Roma), two institutes of the National Research Council (IFAC Florence and IMAA Tito Scalo) and INGV (National Institute of Geology and Vulcanology). The seven proposing teams blend expertise both in experimental and theoretical Atmospheric Sciences, therefore ECOWAR/COBRA has set up an end-to-end methodology which allows us not only to record the observations, but also to analyse them in order to validate atmospheric radiative transfer models and test the quality of water vapour continuum and line parameters. COBRA consists in a series of field campaigns aiming at sensing the water vapour rotational band. The observations will be then used a) to test models of atmospheric radiative transfer in clear and cloudy skies, within the water vapour rotational band, b) to test spectral absorption properties of water vapour in the rotational band from 200 to 600 (cm-1) c) to demonstrate the capability of the aforementioned band as a temperature and humidity sounding system, especially to improve the height discrimination of water vapour concentration. The project plans to integrate observations from the ground to those from satellite platforms, which should allow us to properly define the thermodynamic state of the atmosphere, and, hence, provide the ancillary information to reconstruct the down-welling and upwelling spectral radiance, along with the radiative diabatic effects in clear and cloudy sky

COBRA: Il Contributo Italiano allo Studio Teorico Sperimentale dello Spettro di Emissione Terrestre nella Banda Rotazionale del vapor d'acqua,

Il progetto ECOWAR (Earth COoling by WAter vapour Radiation), secondo il suo acronimo in inglese, o COBRA (Campagna di Osservazioni della Banda Rotazionale del vapor d’Acqua) secondo il suo acronimo italiano, è un programma di campagne di misure che vuole colmare il gap conoscitivo delle proprietà ottiche del vapor d’acqua nella banda rotazionale (17-50 μm).Questo lavoro offre una sintesi dello stato del progetto dopo le campagne di misura di gennaio e marzo 2007. Quest’ultima, la più intensiva, è stata condotta nelle Alpi presso i siti di Cervinia (2000 m) e Testa Grigia (3500 m), che, per l'occasione, hanno accolto la strumentazione adatta ai fini del progetto. La strumentazione consiste in una serie di spettrometri in trasformata di Fourier, capaci di misurare nel range spettrale d'interesse, più un radiometro a microonde e un sistema Raman Lidar per la misura di particolato, temperatura e vapor d'acqua. La campagna ha combinato misure dal suolo e da satellite. Ciò ha permesso di ottenere, insieme alle misure dirette dell'emissione infrarossa dell'Atmosfera nella banda rotazionale del vapor d'acqua, anche i parametri ancillari e complementari, necessari per una corretta definizione dello stato termodinamico dell'Atmosfera. La "chiusura" con dati satellitari, permetterà, e.g., anche la determinazione dei profili di riscaldamento e raffreddamento per scambio radiativo (profili diabatici) a cielo sereno e nuvoloso. ECOWAR/COBRA è un progetto coordinato tra tre Università (due gruppi dell’Università di Bologna, più altri due rispettivamente dall’Università della Basilicata e Roma “La Sapienza”), con la collaborazione di due Istituti del CNR (IFAC di Firenze ed IMAA di Tito Scalo, Pz) e la partecipazione dell’ING