Metoda razlikovanja magle i niske stratusne naoblake pomoću satelitskih podataka i prizemne temperature

master's thesis

• Title (english): Discrimination between fog and stratus clouds using a method based on satellite data and ground measurements
• Author: Marija Cerovečki
• Mentor: Nataša Strelec Mahović (mentor)
• Committee member: Nataša Strelec Mahović (predsjednik povjerenstva)
• Committee member: Maja Telišman Prtenjak (član povjerenstva)
• Committee member: Snježana Markušić (član povjerenstva)
• Committee member: Željko Večenaj (član povjerenstva)
• Committee member: Ines Ivančić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Geophysics); Zagreb
• Defense date and country: 2018-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geophysics; Meteorology and Climatology

Abstract

Nastanak i disipacija, prostorna raspoređenost i dinamika magle vrlo su važne informacije za odvijanje i sigurnost pomorskog,cestovnog i zračnog prometa. Prognoza magle pomoću numeričkih modela za prognozu vremena još je uvijek vrlo zahtjevno područje operativne meteorologije. S druge strane, većina državnih meteoroloških službi automatizira sinoptičke postaje, pa su motrenja koja obavljaju motritelji na postajama, kao što su naoblaka, vidljivost i meteorološke pojave, sve manje dostupna, jer automatske postaje nisu uvijek opremljene instrumentima za mjerenje vidljivosti. Stoga, objektivne metode za razlikovanje magle i stratusne naoblake, temeljene na podatcima daljinskih motrenja, mogu pružiti dodatne informacije potrebne za detekciju i vrlo kratkoročnu prognozu (nowcast) magle. U ovom radu je testirana pretpostavka da je razlika prizemne temperature na 2m visine mjerene na sinoptičkim postajama i temperature vrha stratusnog sloja ili sloja magle, dobivene iz satelitskih podataka, znatno manja u slučajevima s maglom nego u slučajevima sa sumaglicom i stratusnom naoblakom. Dani s maglom, sumaglicom i stratusnom naoblakom izdvojeni su iz sinoptičkih izvještaja i NWCSAF (Nowcasting Satellite Application Facility) CTYPE (Cloud Type) produkta. Za određivanje temperature vrha sloja magle/stratusa korišteni su satelitski podatci s MSG (Meteosat Second Generation) satelita, iz infracrvenih kanala IR8.7, IR10.8 i IR12.0, a podatci o temperaturi zraka na 2m iz sinoptičkih izvještaja prikupljenih s četiri kontinentalne i pet primorskih postaja Hrvatske. Dobiveni rezultati pokazuju da su temperaturne razlike vrha sloja i prizemne temperature znatno manje (∼ 3◦C) u slučajevima magle nego u slučajevima sumaglice i stratusne naoblake.

Abstract (english)

Formation and dissipation, spatial extent and dynamics of fog are very important information for sea, road and air traffic management, especially in terms of traffic safety. Nowcasting and forecasting of fog, using numerical model products, still represent very demanding tasks in the operational meteorology. Since most of national weather services tend to automatize their synoptic weather stations, human observations about current weather, i.e. visibility, fog and low clouds, will become less available. Consequently, an objective method for discrimination between fog and stratus clouds is becoming increasingly important for real time detection, as well as nowcasting of fog. The hypothesis which was tested in this study is that the temperature differences between 2m temperature measured on synoptic weather stations and brightness temperature of the top of fog/low cloud layer is notably different in cases with fog compared to cases with haze or stratus. Days with fog or low clouds were identified using weather observation reports and NWCSAF (Nowcasting Satellite Application Facility) CTYPE (Cloud Type) product. The analysis was done using Meteosat Second Generation satellite data, i.e. infrared channels (IR8.7, IR10.8 and IR12.0) to obtain brigntness temperature, and 2m temperature measurements from four synoptic weather stations in the continental part of Croatia and five weather stations along the coastline. The results showed that differences between 2m temperature and cloud top temperature are significantly lower (∼ 3◦C) in cases with fog, than in those with haze or stratus.

• Keywords: magla; stratus; satelitski podatci
• Keywords (english): fog; stratus; satellite data
• Language: croatian
• URN:NBN: urn:nbn:hr:217:636154
• Study programme: Title: Graduate university study pf Physics - Geophysics; specializations in: Seismology and Physics of the Earth's Interior, Meteorology and Physical Oceanography; Course: Meteorology and Physical Oceanography; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra fizike – geofizike (magistar/magistra fizike – geofizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-10-09 13:46:20