Abstract. Initial objectives and design of the Benchmark campaign organized within European COST Action ES1206 (2013–2017) are described in paper. This has aimed to support development validation advanced Global Navigation Satellite System (GNSS) tropospheric products, particular high-resolution ultra-fast zenith total delays (ZTDs) gradients derived from a dense permanent network. A complex data set was collected for 8-week period when several extreme heavy precipitation episodes occurred...

Foehn is an extreme weather event caused by high wind gusts and its forecasting still a challenge. The foehn in Bulgaria observed on the northern slopes of mountains. Sofia occurs after air mass passes over Vitosha Lulin days are selected using as criteria surface temperature, relative humidity direction. For period 1993–2014 there 136 days. 55.9% gust between 14 19 m/s corresponding to yellow Meteoalarm code, 14.7% with 20–29 (orange code), 1.5% 30 (red code). upper-air flow at mountain...

Recent studies have revealed a rise in extreme heat events worldwide, while cold has shown decline. It is highly likely that human-induced climate forcing will double the risk of severe waves by end century. Although expected to greater socioeconomic impacts than extremes, latter contributes wide range adverse effects on environment, various economic sectors and human health. People can somewhat adapt temperatures when they experience repeated waves, but these more health consequences occur...

Recent studies have revealed a rise in extreme heat events worldwide, while cold has reduced. It is highly likely that human-induced climate forcing will double the risk of exceptionally severe waves by end century. Although expected to more significant socioeconomic impacts than extremes, latter contributes wide range adverse effects on environment, various economic sectors and human health. The present research aims evaluate contemporary spatio-temporal variations Southeastern Europe...

Low visibility caused by fog events can lead to disruption of every type public transportation, and even loss life. The focus this study is the synoptic conditions associated with formation. data used in was collected over course ten years (2010–2019) Sofia, Bulgaria. forecast skills Fog Stability Index (FSI) local Sofia (SSI), as well relation between Integrated Water Vapor (IWV) from Global Navigation Satellite System (GNSS), were tested. Both indices are for nowcasting their times short...

Global Navigation Satellite System (GNSS) is an established atmospheric monitoring technique delivering water vapour data in near-real time with a latency of 90 min for operational Numerical Weather Prediction Europe within the GNSS service (E-GVAP). The advancement processing made quality real-time tropospheric products comparable to near-real-time solutions. In addition, they can be provided temporal resolution 5 and 10 min, suitable severe weather nowcasting. This paper exploits added...

This study presents the results about influence of weather elements on Cloud Condensation Nuclei (CCN) size distribution. For this purpose data for summer (July) and winter (December) conditions 2016 from highest in Balkan Peninsula Environmental Observatory Mt. Moussala are used finding extrema CCN concentrations. To characterize synoptic situation we extend our with geopotential height, wind temperature at 700 hPa considered two months. We use HYSPLIT model National Oceanic Atmospheric...

Severe weather monitoring and forecasting is the prime task of National Meteorological Services according to World Organization Guidelines (WMO). Since 2009 Bulgarian Institute Meteorology Hydrology (NIMH) issues 48 h ahead severe warnings as a contribution European warning system (METEOALARM). A total 243 days with for heat, thunderstorms intense rain were issued period May-September 2010–2019. The monthly maximum heat 42 in July, it 26 June, 27 June. Objective circulation classification...

Severe weather monitoring and forecasting is the prime task of National Meteorological Services according to World Organization Guidelines (WMO).  Since 2009 Bulgarian Institute Meteorology Hydrology (NIMH) issues 48 h ahead severe warnings as a contribution European warning system (METEOALARM). A total 243 days with for heat, thunderstorms intense rain were issued Sofia, Bulgaria period May-September 2010-2019. The monthly maximum heat 42 in July, 26 June 27 June. yearly 21 2012...

Global Navigation Satellite System (GNSS) is an established atmospheric monitoring technique delivering water vapour data in near-real time with a latency of 90 min for operational Numerical Weather Prediction Europe within the GNSS service (E-GVAP). The advancement processing made quality real-time tropospheric products comparable to near-real-time solutions. In addition, they can be provided temporal resolution 5 and 10 min, suitable severe weather nowcasting. This paper exploits added...

According to the Sixth Assessment Report of Intergovernmental Panel on Climate Change aerosols are having generally a negative but decreasing in magnitude contribution effective radiative forcing (ERF) and, therefore, they act against global warming. Leading role this ERF balance play involved aerosol-cloud interaction, named cloud condensation nuclei (CCN). In present article we study distribution CCN as monitored by Basic Environmental Observatory Musala 2016 and their performance...

Cloud condensation nuclei (CCN) are aerosols involved in the cloud formation. The distribution of CCN at top mountains could be indicative for transport air masses that influence respective region. main purpose this study is to apply Twomey’ power-law dependence NCCN = CSk concentration CCN, NCCN, measured Basic Environmental Observatory Moussala a specific supersaturation ambient S. Due its location, observatory situated layer majority year. Correlation coefficients found between prefactor...


 Fog can cause large economic losses for public services and in particular aviation where the cost of flight delays rescheduling is estimated to hundreds millions euros per year. Despite continuous improvement weather prediction fog diagnosis forecasting remains a challenge. In US alone, 74% fatal car crashes are associated with recorded low visibility but without warning forecast. Today operational mainly done “in-house” developed tools, which understandable due life cycle...

<p>Despite the continuous improvement of weather prediction fog diagnosis and forecasting remains a challenge with large economic losses for public services in particular aviation where cost flight delays rescheduling is estimated to hundreds million euros per year. Today operational mainly done "in-house" developed tools, which understandable due life cycle peculiarity. The aim this work investigate climatology Plovdiv, Bulgaria period 1991 - 2018 use it...