Peter Nojarov

Peter Nojarov
National Institute of Geophysics, Geodesy and Geography, Bulgarian Academy of Sciences · Geography

PhD

About

37
Publications
4,435
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190
Citations
Citations since 2017
15 Research Items
154 Citations
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20172018201920202021202220230102030
20172018201920202021202220230102030

Publications

Publications (37)
Article
Full-text available
This study focuses on the strengthening of the maritime influence on the Balkan Peninsula in summer. The study uses mainly statistical methods such as trend analysis, multiple linear regression models, etc. The research period is 1979–2020. The results show that in the beginning of the twenty-first century in southeastern Europe there is a tendency...
Article
Full-text available
This study reveals the dynamics in the number and intensity of heat waves in Bulgaria in the late 20th and early twenty-first century, as well as their impact on forest fires in the beginning of this century. Statistical methods such as linear regression and Spearman’s correlation were the main tools of this study. Multiple linear regression models...
Article
Full-text available
The widely used Global Historical Climatology Network (GHCN) monthly temperature dataset is available in two formats - non-homogenized and homogenized. Since 2011, this homogenized dataset has been updated almost daily by applying the "Pairwise Homogenization Algorithm" (PHA) to the non-homogenized datasets. Previous studies found that the PHA can...
Article
Full-text available
The area of the Seven Rila Lakes is situated in the North-West part of the Rila Mountain at an altitude between 2100 and 2500 m a.s.l. within the borders of Rila National Park. There are 140 glacial lakes in Rila Mountain but the area of the Seven Rila Lakes is the most visited and famous with its natural beauty and sacred significance. It is a val...
Article
Full-text available
This study reveals the effect of aerosols and water vapor on downward longwave radiation in the high mountain region of Musala peak, Bulgaria. The investigated period is 01/01/2017 (Jan. 1 st 2017)-30/09/2019 (Sep. 30 th 2019). Statistical methods are the main tool for discovering the relationships between the different elements. The results indica...
Article
Full-text available
This study reveals changes in atmospheric circulation over the western part of the Black Sea during the period 1979–2019 and related changes in wind conditions and sea wave in the active tourist season, which at the Bulgarian coast spans from June to September. Statistical methods such as linear regression and Spearman's correlation are used. There...
Article
The aim of this study is to reveal the direct radiative effect of aerosols on global solar shortwave radiation in the region of peak Musala, which has specific climatic and environmental conditions. Correlations between the measured global solar shortwave radiation and the total aerosol content, Ångström exponent in the visible spectrum, absorption...
Article
Full-text available
This study reveals the influence of some climatic elements on radon concentration in Saeva Dupka Cave, Bulgaria. The research is based mainly on statistical methods. Radon concentration in the cave is determined by two main mechanisms. The first one is through penetration of radon from soil and rocks around the cave (present all year round, but has...
Article
Full-text available
This study reveals the climate and its changes in the period 1979-2018 in the following karst regions in Bulgaria-Devetashko Plateau, Brestnishka Karst Geosystem, Trigrad, Dab-rash and Shumensko Plateau. Statistical methods are the main tool in this research. The climate of the five model karst regions is largely dependent on their location, especi...
Article
Full-text available
The research period is 1984–2007 and includes data for air temperatures at 20 Bulgarian and Serbian stations. Also, data for four radiation fluxes and cloud fraction were used in the study. Atmospheric circulation is represented by six different circulation patterns and indices. Statistical methods such as principal component analysis, trend analys...
Article
This research reveals relationships between climate variables and inter-annual dynamics in the area of the glacieret located in the cirque Golemiya Kazan in the Pirin Mountains. The study period is 1993–2017. The correlations are identified using statistical methods. Also, a statistical model is constructed, including some climate variables as pred...
Article
Full-text available
This study determines the influence of greenhouse gases and aerosols in the atmosphere over Bulgaria on different radiation fluxes at Earth's surface, and on near surface air temperature. The research period is 09.2002-12.2015. Data for observed air temperature in Bulgaria, specific humidity at different levels, content of CO 2 and CH 4 in atmosphe...
Article
Full-text available
The study analyzes changes in September precipitation in the Mediterranean region and their possible causes. The research period is 1950–2014. The main finding is that the reduction in aerosol pollution over Europe in the late twentieth century has led to an upward shift of air temperatures in the region, which in turn has reduced the meridional te...
Article
Sea Level Pressure (SLP) data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses that are situated over the Balkan Peninsula during the year. The method for differentiation of climatic zones is cluster analysis. A hi...
Conference Paper
Full-text available
The aim is to analyze and evaluate tourism practices in selected model areas (Nature park Shumensko plato (Bulgaria) and PLA Moravský kras (Czech Republic) through the specifics of vulnerable karst areas in regard to sustainable development and sustainable tourism in these territories. The ensuing comparative assessment of tourism practices between...
Article
Full-text available
The article reveals temporal and spatial trends in greenhouse gases and aerosols in the atmosphere over Bulgaria. The period of study is from 09.2002 to 12.2015, and it is determined by the available database, which is based mainly on satellite measurements. Carbon dioxide and methane are measured by the instrument AIRS (Atmospheric Infrared Sounde...
Article
The objective of this paper is to determine the influence of circulation factors on precipitation in Bulgaria. The study succeeds investigation on the influence of circulation factors on air temperatures in Bulgaria, as the focus here is directed toward precipitation amounts. Circulation factors are represented through two circulation indices, show...
Article
Full-text available
This article examines spatial and temporal distribution of cloudiness and sunshine duration in Bulgaria. The period of investigation of contemporary state of these two climatic elements is 1999–2013 for sunshine duration, 1984–2007 for cloudiness according to satellite data and 1999–2014 for cloudiness according to ground based observations. Low an...
Article
The research period is 1950–2012, and includes data for air temperatures in 21 Bulgarian stations. Two circulation indices, covering the same period and showing west–east or south–north directions of transport of air masses, were calculated. Statistical methods were used in the study. The results show a significant positive trend in average annual...
Article
Full-text available
Characterization of climate of the region was made using data for the last 30-year period (1984–2013) from two meteorological stations - Silistra and Calarasi. Satellite data for different radiation fluxes (shortwave and longwave) and cloudiness were also used. Main research methods are statistical. Shortwave radiation fluxes in the study area show...
Article
Air temperature and precipitation data from three high mountainous Bulgarian stations were used as well as outputs from nine regional climate models (RCMs) for air temperatures and eight RCMs for precipitation. Data from 40-year experiments driven by the ERA-40 reanalysis (temporal coverage from 1961 to 2000) of the ECMWF were employed for calibrat...
Conference Paper
Full-text available
A comparison of three ways of measurement of precipitation at station NIGGG – with rain gauge, pluviograph and automatic weather station was made. Atmospheric circulation over Bulgaria is determined by an index based as a way of calculation on the index of the North Atlantic Oscillation. Spatial distribution of annual precipitation is shown. The re...
Article
Some connections between aerosols, atmospheric transport, and relative humidity are investigated based on measurements at Basic Environmental Observatory (BEO) station, peak Musala (2,925 masl) for the period January 2009–January 2010. Data are chosen at 0:00 and 12:00 GMT every day. Main methods employed in this research are statistical—nonparamet...
Article
Trends in atmospheric pressure, circulation and some relationships between North Atlantic Oscillation (NAO) indices, sea surface temperatures, and atmospheric circulation over Bulgaria are discussed in this article. Data for measured atmospheric pressure at stations Burgas, Pleven, and Sandanski are used. Information about atmospheric circulation o...
Conference Paper
Full-text available
Regional Climate Models were downscaled for the region of Rila using statistical modeling. Projections for the future course of air temperatures and precipitation were made. The impact of these two factors on the temperature of the surface water layer and the levels of Seven Rila Lakes was assessed.
Article
Measured air temperature and precipitation data from three high mountainous Bulgarian stations were used along with data from 18 global climate models (GCMs). Air temperature and precipitation outputs of preindustrial control experiment were compared with actually observed values. GCM with the best overall performance is BCCR BCM 2.0 for air temper...
Article
Changes of air temperatures and atmosphere circulation at three high mountainous stations in Bulgaria are investigated for the period of 1941–2008. The three stations are located on peaks Musala, Cherni vrah and Botev, where air temperature data have good quality. Some missing data were recovered using the method of differences. A significant mean...
Article
Variations of precipitation amounts, atmosphere circulation, and relative humidity at three high mountainous stations in Bulgaria are investigated. The research period is 1947–2008. Three stations are peaks Musala (2,927m), Cherni Vrah (2,293m), and Botev (2,378m). Homogeneity checks were performed. Some adjustments of monthly precipitation amounts...
Article
Full-text available
The changes of air temperature at peak Moussala for the period 1933-2008 are investigated. The peak area is away from possible anthropogenic impacts. That's why temperature fluctuations are natural and represent trends of large scales – from regional to global. Both mean annual and mean monthly air temperatures are investigated in order to achieve...
Article
Connection between ozone concentration and atmosphere circulation is investigated based on measurements at BEO station, peak Moussala (2,925 m a.s.l.), for the period 09 August 2006 to 29 January 2008. Ozone concentration data are collected with UV-analyzer “Environnement O3 42” and meteo data with weather station “Vaisala”. There are measurements...
Article
Full-text available
The article presents results of a bathymetry mapping of Ledenoto ezero in Rila Mountain that took place in summer 2008. Situated at 2709 m a. s. 1. at the north eastern foot of Musala peak, Ledenoto ezero (the Icy Lake) is the highest lake in Rila and the second highest in Bulgaria. The expedition work, which is summarized in the detailed map elabo...
Article
Full-text available
Tornado is one of the most dangerous and destructive atmospheric disasters, which could be encountered in Bulgaria. It is vortex around vertical axis, which is developed between the cloud and earth surface. Sharp temperature, moisture and density contrast between the air masses is necessary to form a tornado. It is most common over the southeast pa...

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Projects (2)
Project
Global changes and the problems they cause are an incontestable fact in our times, and they also affect karst. It is widespread but it is also specific in that it builds risk areas with very high vulnerability. The aim of this project proposal is to identify and explore the system of global changes that have an impact on the evolution of karst on a regional and local scale. For their registration, analysis and evaluation model karst geosystems are used, representative of different karst types, with integrated monitoring organized in them. If they are affected by global change, it also affects the lives of people on these territories. At the same time, people with their activities are also part of global change and have their impact on karst geosystems, most often deepening their problems. These complex relationships make the subject of this project. For their exploration, analysis, evaluation and modeling, an interdisciplinary international team of professionals with rich experience has been formed. On the principle of synergy, they will join forces in the implementation of a geosystem approach. Team members have scientific competencies and have developed a number of original theoretical-methodological questions and innovative ideas in their previous research. Some of them (the concept of karst geosystems, the ProKARSTerra paradigm, the model for integrated monitoring of karst systems MIKC, etc.) make a methodological platform for the development of the proposed project., There are three major accents in its working program, namely: Theoretical-Methodological, Experimental (Field and Laboratory) and Applied ones. Fundamental research has revealed some trends and developed theoretical models for both the impacts of global change on the karst evolution and the role of karst genesis in global change (including through the carbon cycle), i.e. the feedback is also studied. On the basis of the results achieved, scientifically justified measures, policies and models for sustainable development of karst territories in the context of global changes will be developed and proposed.
Archived project