Comparing microphysical/dynamical outputs by different cloud resolving models: impact on passive microwave precipitation retrieval from satellite

International audienceMesoscale cloud resolving models (CRM's) are often utilized to generate consistent descriptions of the microphysical structure of precipitating clouds, which are then used by physically-based algorithms for retrieving precipitation from satellite-borne microwave radiometers. However, in principle, the simulated upwelling brightness temperatures (TB's) and derived precipitation retrievals generated by means of different CRM's with different microphysical assumptions, may be significantly different even when the models simulate well the storm dynamical and rainfall characteristics. In this paper, we investigate this issue for two well-known models having different treatment of the bulk microphysics, i.e. the UW-NMS and the MM5. To this end, the models are used to simulate the same 24-26 November 2002 flood-producing storm over northern Italy. The model outputs that best reproduce the structure of the storm, as it was observed by the Advanced Microwave Scanning Radiometer (AMSR) onboard the EOS-Aqua satellite, have been used in order to compute the upwelling TB's. Then, these TB's have been utilized for retrieving the precipitation fields from the AMSR observations. Finally, these results are compared in order to provide an indication of the CRM-effect on precipitation retrieval

Multi-sectoral Impact Assessment of an Extreme African Dust Episode in the Eastern Mediterranean in March 2018

In late March 2018, a large part of the Eastern Mediterranean experienced an extraordinary episode of African dust, one of the most intense in recent years, here referred to as the “Minoan Red” event. The episode mainly affected the Greek island of Crete, where the highest aerosol concentrations over the past 15 yeas were recorded, although impacts were also felt well beyond this core area. Our study fills a gap in dust research by assessing the multi-sectoral impacts of sand and dust storms and their socioeconomic implications. Specifically, we provide a multi-sectoral impact assessment of Crete during the occurrence of this exceptional African dust event. During the day of the occurrence of the maximum dust concentration in Crete, i.e. March 22nd, 2018, we identified impacts on meteorological conditions, agriculture, transport, energy, society (including closing of schools and cancellation of social events), and emergency response systems. As a result, the event led to a 3-fold increase in daily emergency responses compare to previous days associated with urban emergencies and wildfires, a 3.5-fold increase in hospital visits and admissions for Chronic Obstructive Pulmonary Disease (COPD) exacerbations and dyspnoea, a reduction of visibility causing aircraft traffic disruptions (eleven cancellations and seven delays), and a reduction of solar energy production. We estimate the cost of direct and indirect effects of the dust episode, considering the most affected socio-economic sectors (e.g. civil protection, aviation, health and solar energy production), to be between 3.4 and 3.8 million EUR for Crete. Since such desert dust transport episodes are natural, meteorology-driven and thus to a large extent unavoidable, we argue that the efficiency of actions to mitigate dust impacts depends on the accuracy of operational dust forecasting and the implementation of relevant early warning systems for social awareness

Multi-sectoral impact assessment of an extreme African dust episode in the Eastern Mediterranean in March 2018

In late March 2018, a large part of the Eastern Mediterranean experienced an extraordinary episode of African dust, one of the most intense in recent years, here referred to as the “Minoan Red” event. The episode mainly affected the Greek island of Crete, where the highest aerosol concentrations over the past 15 yeas were recorded, although impacts were also felt well beyond this core area. Our study fills a gap in dust research by assessing the multi-sectoral impacts of sand and dust storms and their socioeconomic implications. Specifically, we provide a multi-sectoral impact assessment of Crete during the occurrence of this exceptional African dust event. During the day of the occurrence of the maximum dust concentration in Crete, i.e. March 22nd, 2018, we identified impacts on meteorological conditions, agriculture, transport, energy, society (including closing of schools and cancellation of social events), and emergency response systems. As a result, the event led to a 3-fold increase in daily emergency responses compare to previous days associated with urban emergencies and wildfires, a 3.5-fold increase in hospital visits and admissions for Chronic Obstructive Pulmonary Disease (COPD) exacerbations and dyspnoea, a reduction of visibility causing aircraft traffic disruptions (eleven cancellations and seven delays), and a reduction of solar energy production. We estimate the cost of direct and indirect effects of the dust episode, considering the most affected socio-economic sectors (e.g. civil protection, aviation, health and solar energy production), to be between 3.4 and 3.8 million EUR for Crete. Since such desert dust transport episodes are natural, meteorology-driven and thus to a large extent unavoidable, we argue that the efficiency of actions to mitigate dust impacts depends on the accuracy of operational dust forecasting and the implementation of relevant early warning systems for social awareness.Thanks are due to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020+UIDB/50017/2020) through national funds, and also to the Icelandic Research Fund for the grant no. 207057-051. Authors S. Kazadzis and P. Kosmopoulos would like to acknowledge the European Commission project EuroGEO e-shape (grant agreement No 820852). Also, International Cooperative for Aerosol Prediction (ICAP) and NASA mission researchers are gratefully for providing aerosol data for this study. Aurelio Tobias was supported by MCIN/AEI/10.13039/501100011033 (grant CEX2018-000794-S). S. Kutuzov acknowledges the Megagrant project (agreement No. 075-15-2021-599, 8.06.2021)

Exploring the effects of different types of model initialisation: Simulation of a severe air-pollution episode in Athens, Greece

A combined modelling system consisting of a meteorological model (Colorado State University/ Regional Atmospheric Modelling System) and a transport package (Hybrid Particle and Concentration Transport Model) is used. The simulations were performed using two types of model initialisation: the first with ECMWF gridded analysis data and the second with one sounding profile. The modelling system has been used to simulate an important air-pollution episode in the Athens urban area. This area is characterised by complex and variable topographic features, and the associated local atmospheric circulations play a significant role in defining the transport and dispersion conditions over the area. The advantages and shortcomings of both types of initialisation, and more specifically the capability of the model to represent and reproduce the local-scale conditions and the dispersion of air pollutants, are discussed

Analysis of climatological and air quality observations from Greater Athens Area

In this paper, the climatological and air quality observations obtained for the periods 1974-1990 and 1983-1990, respectively, in the Greater Athens Area, are analyzed. During this period, 80 air pollution episodes, which lasted 210 d in total, were detected. The analysis of the observations allows the interpretation of air quality characteristics in terms of the climatological and meteorological factors. The importance of some characteristic indices for air pollutant dispersion conditions, such as mixing height, ventilation coefficient, temperature at 850 hPa, and temperature inversions, is discussed. The results show that the air quality in the Athens Basin is strongly affected by the meteorological conditions, especially those which are in favor of local circulations. The worst air pollution episodes are associated with anticyclonic conditions and/or advection of warm air masses. © 1995

Model investigation of a cloudband associated with a cold front over Eastern Mediterranean

The aim of this paper is to investigate the occurrence of a cloudband associated with a cold front over the maritime area south from the Greek Peninsula. This cloudband was clearly evident on the infrared satellite picture, oriented nearly parallel to the frontal surface. The relevance of Conditional Symmetric Instability as a possible mechanism for the formation of this band is investigated through model simulations. The model analysis was performed with the three dimensional non-hydrostatic Colorado State University - Regional Atmospheric Modelling System (CSU-RAMS). Inspection of the moist potential vorticity pattern within a cross-section perpendicular to the cloudband supported the hypothesis that Conditional Symmetric Instability was the mechanism which favoured the band formation at the leading edge of the cold frontal surface

Convergence zones over the Greek peninsula and associated thunderstorm activity

In the frame of this study, the initiation of summer storm activity over the Greek peninsula during a prevailing weak synoptic flow is investigated using the Colorado State University-Regional Atmospheric Modelling System. On 10 July 1994, thunderstorm activity was observed along a convergence zone which had developed following the main axis of the peninsula. The convergence zone first deepened the moist layer locally, providing a region potentially favourable to deep convection, while terrain variability and diurnal differential-heating-forced vertical motions. The cold air intrusion aloft, associated with the low-level convergence, resulted in deep convection and significant storm activity. The origin of the moist air masses which fed this activity has been investigated through simulations with a Lagrangian particle dispersion model. Moist air masses, which originated from marine boundary-layer of the Ionian Sea on the west, and north Aegean Sea on the east of the Greek peninsula, were transported over the land through the sea-breeze mechanism and later, at the time of the storm activity, were deeply injected into the troposphere over the convergence line, at heights up to 5 km

Convergence zones over the Greek peninsula and associated thunderstorm activity

In the frame of this study, the initiation of summer storm activity over the Greek peninsula during a prevailing weak synoptic flow is investigated using the Colorado State University-Regional Atmospheric Modelling System. On 10 July 1994, thunderstorm activity was observed along a convergence zone which had developed following the main axis of the peninsula. The convergence zone first deepened the moist layer locally, providing a region potentially favourable to deep convection, while terrain variability and diurnal differential-heating-forced vertical motions. The cold air intrusion aloft, associated with the low-level convergence, resulted in deep convection and significant storm activity. The origin of the moist air masses which fed this activity has been investigated through simulations with a Lagrangian particle dispersion model. Moist air masses, which originated from marine boundary-layer of the Ionian Sea on the west, and north Aegean Sea on the east of the Greek peninsula, were transported over the land through the sea-breeze mechanism and later, at the time of the storm activity, were deeply injected into the troposphere over the convergence line, at heights up to 5 km