Giorgi Kordzakhia

Glacier degradation is an effective indicator of current climate change. The authors,

based on this and previous studies concluded that modern climate change has a significant negative impact on the glaciers of Georgia and causes their intense degradation. To obtain a scientifically substantiated answer to the problem of glacier degradation, the authors used high-resolution satellite remote sensing, since this innovative technology allows a detailed study of glaciers with the required accuracy and spatial-temporal resolution. For a detailed description of the impact of global warming on glacier degradation, the following have been studied particularly: 1. Statistics of melting of small glaciers (area from 0.1 to 0.5 km2); 2. Changes in the area and number of glaciers in glacial basins;

3. Retreat of large glaciers (area> 2 km2). The relevant quantitative data, analysis and generalization of the recerived data are presented.

The results of a study on the impact of current climate change on Georgian glaciers based on high-resolution satellite remote monitoring are presented. Historical data, field observations, glacier catalog, topographic maps, geoinformation systems technologies, and expert knowledge are used to study climate change impacts on glaciers in addition to high-resolution satellite remote sensing information. Results have been obtained which indicate that glacier degradation is nonlinear in nature and significantly accelerated. This finding is in line with one of the main theses of the IPCC Report 6 that the main problem is not climate change but its speed.

Based on the performed research, the following was determined:

1. As a result of the current climate change, the regression of the great glaciers of Georgia is non-linear in nature;

2. The scenario of climate change in accordance with normal business (Business as Usual / BaU /) is used to determine the probable dates of complete melting of the considered large glaciers. Studies have shown that the regression of the considered glaciers under the conditions of this scenario is possible with great accuracy by the parabola curve;

3. Using the equations obtained, the approximate dates of complete melting of some large glaciers are calculated.

From the beginning of the 21st century, glaciers studies are more important in Georgia. This is mainly provided with the degradation of the glaciers under current climate change that preconditions several catastrophic events: sea-level rise, worsening of glacial origin natural disasters risks and catastrophic phenomena, water balance changes etc. Impact of current climate change on the glaciers and their rapid degradation is studied determining the changes of the characteristics of the glaciated basins (number of glaciers and area), the melting statistics of small glaciers (area in the range of 0.1 to 0.5 km2 ) and the retreat of large glaciers (area > 2 km2 ) that are effective indicators of the regional climate change. In order to provide a scientifically based answer to the problem of glaciers melting under the impact of current climate change, it is necessary to use high-resolution satellite remote sensing (SRS), because it makes possible to study simultaneously glaciers for large regions with the necessary resolution and accuracy within limited resources and time. This is achieved based on the complex use of historical data, glacier schemes from the catalogue, existing fieldwork materials and the application of expert knowledge. In presented work, r. Mtkvari basin glaciers degradation due to the impact of the current climate change is studied. Changes in the glacier basins and melting statistics are researched. This is preconditioned by the fact that r. Mtkvari basin is the most important river basin of eastern Georgia and such detailed study has not actually been carried out for any river basin in Georgia.

The dynamics of degradation of the river Pirikiti Alazani glacial basin glaciers is discussed on the background of the current climate change. Based on the integrated survey, the state of the glaciers in this basin at the initial (at the time of issuing of the catalogue -1964), medium (2006) and final (2020) time points are given. The characteristics of the glaciers (number, area) at the medium and final moments are determined using high-resolution satellites. A comparison of these conditions showed that climate change is non-linear, making glacier degradation more intense in the second period than in the first one. If the number of glaciers has shrunk by 28.6% in the first 50 years of the 60 years, correspondingly this reduction is 70% over the last decade. If during the first period the area covered by glaciers decreased by 56%, in the second period it decreased by 75.7%. This can be explained by two factors: first, that climate change development has non-linear character and second, that climate change impacts on smaller glaciers are more intense.

Current climate change has a very negative impact on the cryosphere, in particular on the glaciers. This has dire consequences for the world, in particular, the landscape changes, glacial runoff decreases, the frequency and magnitude of natural glacial events increases. To characterize the impact of current climate change on glaciers, one of the effective approaches is to study the dynamics of change (decrease) of the glacial basins. This is possible by comparing information (data about glaciers areas) available in the past with information determined at present. For this study, as the initial data, we use the data available from the catalogue. For characterizing the dynamics of degradation of glacial basins of rivers Assa and Arguni earlier, we have conducted works using satellite data processing and determined the condition and characteristics of Georgian glaciers for 2006−2015 (medium condition). For data accuracy (QA/QC) in mentioned researches along with satellite remote sensing (SRS) information, historical data and expert knowledge were used. For having the final condition characterizing along with the initial and medium condition the dynamics of glaciers we added new data from 2020 (final data) using Landsat 8 satellite images. A comparison of these conditions showed that climate change speed is non-linear, making glacier degradation more intense in the second period than in the first one. 

In Georgia, on the ridge of the Greater Caucasus, there are well-developed, rather high glaciers. The study of glaciers has gained more importance since the second half of the twentieth century due to the negative impact of current climate change, which has led to significant and rapid degradation of glaciers, exacerbating natural disasters of glacial origin. Due to the degradation of glaciers in the country, a change in the water balance and degradation of landscapes, an increase in the level of the Black Sea, and the growth of the natural disasters frequency and intensity of glacial origin are having a place. This poses a serious threat to the sustainable development of the country and, therefore, the study of glaciers has become a priority in the research program of Georgia. Using satellite remote sensing, GIS technologies, glacial catalogue, field ground observations and expert knowledge, the negative impact of modern climate change was revealed and, as a consequence, the dynamics of degradation of glaciers in the glacial basins of East Georgia was studied in detail. In this article, the dynamics of the degradation of glaciers in the glacial basins of River Terek is overviewed. For this purpose, a comparison is made of the state of glaciers (area and number) for three time periods. The initial state is taken to be the state of glaciers in this basin at the time of the finish of the glaciers researches (1960). The data gathered were published in several editions of the glacier catalogue. Subsequent states - middle (2015) and final (2020) are determined using high-resolution satellites. Technological and methodological research proved to be effective for studying the dynamics of glacier degradation based on innovative high-resolution satellite remote sensing since the best practices were used in conjunction with the methods developed by the authors. A comparison of these conditions showed that the area and number of glaciers are greatly decreasing due to climate change. It should be noted that the dynamics of glacier degradation is nonlinear, which makes the melting of glaciers in the second period more intense than in the first. This conclusion also confirms one of the main theses of the 6th IPCC report that the main problem is not climate change, but its speed.

1. The comparison of the SRS data with the topographic maps dated 1960-1970 shows that over the last 50 years the area of all glaciers in Georgia has shrunk;

2. The 50-year time difference between the SRS and catalogue data allows to assess changes in glacial basins and small glacier melting;

3. Calculations conducted for the glacial basins show that the area and number of glaciers have decreased and that this process is more intensive in eastern regions than in Western Georgia;

4. Small glacier melting analysis shows that melting goes intensively under the impact of the climate change and that in Eastern Georgia this process is more intensive than in the western regions;

5. The retreat dynamics and trends of large glaciers have been quantitatively analyzed for the period of 40- 50 years. The detailed analysis shows that all large glaciers are retreating in both Eastern and Western Georgia;

6. Analysis of glacier retreat trends based on the SRS and field data shows data compliance, therefore we can make reasonable assumptions that SRS-based quantitative characteristics of the retreat of large glaciers are valid and reliable;

7. The analysis of the two observation sub-periods shows that during the second sub-period the retreat of large glaciers has accelerated in both Eastern and Western Georgia, while degradation of large glaciers is more active in Eastern Georgia compared to the western part of the country;

8. Glacier degradation process in Eastern Georgia is more intensive than in Western Georgia, which is true both for glacial basins as well as for large and small glaciers. This can be explained by the climatic differences - the continental climate in Eastern Georgia and marine humid climate in Western Georgia;

9. One of the climate change scenarios determines tentative dates for possible ultimate melting of large glaciers.

Glacier degradation is an effective indicator of current climate change. The authors, based on this and previous studies concluded that modern climate change has a significant negative impact on the glaciers of Georgia and causes their intense degradation. To obtain a scientifically substantiated answer to the problem of glacier degradation, the authors used high-resolution satellite remote sensing, since this innovative technology allows a detailed study of glaciers with the required accuracy and spatial-temporal resolution. For a detailed description of the impact of global warming on glacier degradation, the following have been studied particularly: 1. Statistics of melting of small glaciers (area from 0.1 to 0.5 km2); 2. Changes in the area and number of glaciers in glacial basins; 3. Retreat of large glaciers (area> 2 km2 ). The relevant quantitative data, analysis and generalization of the recerived data are presented.

 Glaciers are an important natural resource, as they contain large amount of fresh water. It is determined that the glaciers degradation is accelerated under the impact of current climate change. High resolution satellite remote sensing is used to conduct scientifically based studies to detect the effects of current climate change on the state of large glaciers in Georgia. This makes possible, in conditions of limited resources and time, to simultaneously study glaciers with the necessary resolution and accuracy. It is determined that the retreat of the large glaciers Gergeti (Eastern Georgia) and Adishi (Western Georgia) is non-linear in nature and this process is more active in eastern Georgia than in its western part. According to one of the climate change scenarios, the estimated dates of their complete melting are determined.

Glacier degradation is an effective indicator of ongoing climate change. To promote the sustainable development of the country, it is necessary to develop a strategy for adapting to glacier-related natural disasters and to take mitigation measures in the most vulnerable mountainous regions. To do this, it is important to have the results of a scientifically substantiated glacier degradation study.

The scientific study of glaciers in Georgia began in 1860. The results of these researches have been summarized and listed in the Catalog of Glaciers of the Former Soviet Union in 1960-77.

The scientifically sound answer to the problem of glacier degradation under the influence of current climate change requires the use of high-resolution satellite remote sensing (SRS), as SRS allows the simultaneous study of glaciers for large regions with limited detail and accuracy.

Determination of glacier characteristics and their dynamics is achieved in combination with high-resolution SRS based on complex historical data, existing fieldwork, and integrated, integrated application of expert knowledge.

The number of glaciers and their areas under the impact of current climate change on glacial basins and small glaciers is given. The retreat dynamics of some large glaciers are given. Based on these dynamics and the climate change scenario called business as usual (BaU) the complete melting dates for these glaciers are estimated.

It has been found that the area of glaciation and the number of glaciers in Georgia has decreased and this decrease is more intense in Eastern Georgia than in Western Georgia. It has been shown that under the conditions of climate change the regression of large glaciers is accelerated and the estimated dates of complete melting of individual glaciers are determined, and the relationship between the regression of large glaciers and climate change is determined.

From the beginning of the 21st century, glaciers studies are more important in Georgia. This is mainly provided with the degradation of the glaciers under current climate change that preconditions several catastrophic events: sea-level rise, worsening of glacial origin natural disasters risks and catastrophic phenomena, water balance changes etc. Impact of current climate change on the glaciers and their rapid degradation is studied determining the changes of the characteristics of the glaciated basins (number of glaciers and area), the melting statistics of small glaciers (area in the range of 0.1 to 0.5 km2 ) and the retreat of large glaciers (area > 2 km2 ) that are effective indicators of the regional climate change. In order to provide a scientifically based answer to the problem of glaciers melting under the impact of current climate change, it is necessary to use high-resolution satellite remote sensing (SRS), because it makes possible to study simultaneously glaciers for large regions with the necessary resolution and accuracy within limited resources and time. This is achieved based on the complex use of historical data, glacier schemes from the catalogue, existing fieldwork materials and the application of expert knowledge. In presented work, r. Mtkvari basin glaciers degradation due to the impact of the current climate change is studied. Changes in the glacier basins and melting statistics are researched. This is preconditioned by the fact that r. Mtkvari basin is the most important river basin of eastern Georgia and such detailed study has not actually been carried out for any river basin in Georgia.

he obtained results reflect the influence of the climate change on the conditions of Georgia's small glaciers. The study concluded that all small glaciers decrease or completely disappear and this process of glaciers melting is more active in Eastern Georgia than in its western part.

Satellite Earth observations (EO) are important tool for application of remote sensing technologies to various environmental issues and glaciology in particular. Glaciers play an important role in formation of the climate at regional and global scales. Glaciers variations are clear indicator of the anticipated climate change. Satellite EO are significant for determination of glaciers characteristics. In past researches the terrestrial observations were used. Corresponding field works were difficult to organize that resulted in data irregularity both in terms of space and time resolution as well as in data uncertainities. Satellite EO is more or less free of these limitations. Satellite remote sensing give possibility to research not only the main glaciers located in the region but satellite EO is successful tool to study small glaciers as well. In the article the small glaciers main characteristics: length, area, minimum and maximum elevation, firn line elevation, ablation and accumulation areas are determined using the satellite EO processing based on GIS technologies. Therefore the necessity for quality assessment/quality control (QA/QC) remains. Based on several researches it is established that the best technology for detailed and precise study of small glaciers is the satellite EO combined with ground observations and expert knowledge.

Based on the satellite Earth observations and GIS technologies the changes in the glaciers of East Georgia under the influence of regional climate change are considered. It should be noted that in the past the glacier parameters (area, length and volume) increased. It was determined that during the second half of the last century the characteristics of Georgian glaciers are steadily diminishing due to the impact of global warming. M. Sylvén, et all. researched that the glaciers’ total area in Georgia decreased by 36% and their volume - by 48%. This process is still underway and most likely will continue in the future. In the past glaciers researches were carried out mainly based on terrestrial observations that were characterized by the significant shortcomings: high expanses, data irregularity both in terms of space and time resolution. Satellite Earth observations (EO) are practically free of these limitations. The impact of modern regional climate change on small glaciers melting and large glaciers retreat is researched. It is determined that over the past 50 years, approximately 70% of the small glaciers of East Georgia completely or partly melted under the impact of regional climate change. A significant increase of the rate of large glaciers retreat is determined, especially for the latest 15 years. These results obviously indicate degradation of glaciers under the accelerated impact of regional climate change. 

Summarizing, it can be concluded that the glaciers of East Georgia have been intensively melting under the impact of regional climate change. Medium glaciers are becoming small glaciers, small glaciers are turning into snowfields or completely vanishing, and the large glaciers are degrading and retreating. At least 70% of identified small glaciers in East Georgia are now snowfields or fully melted. Analysis of large glaciers shows that the rate of their retreat has increased. The analysis and comparison of retreat rates between the second and first periods show that the glacial retreat rate has increased significantly. We conclude that during the last 15 years, retreat has increased substantially when compared to the first period. This research reveals the acceleration of regional climate change.

NMHS of Georgia closely cooperates with the European Meteorological Satellite (EUMETSAT) organization, which is reflected in regular participation in workshops organized by EUMETSAT both in Georgia (2015–2016) and abroad (Macedonia 2013). Naturally, this close cooperation will continue in the future.

Presents the direct and indirect methods of determining the firn line of mountain glaciers according to ground-based observations. The methodology of determination of the firn line of mountain glaciers according to satellite remote sensing is established. The mathematical formula to determine the height of the firn line using the complex data of the catalog of glaciers and satellite observations. The results of this study shows that the presented methodology is effective. 

The problem of the transportation safety for Mtskheta-Stepantsminda-Larsi road is overviewed. The scientific study of glaciers in the Caucasus started in the first half of the 19th century. From that time the terrestrial observations on glaciers were carried out. The data received contain uncertainties and have no sufficient resolution in time and space. With the invention of the Earth’s satellites it was determined that satellite remote sensing is the best technology allowing to receive the data with needed regularity both in terms of time and space resolution. The results of various researches show that sometimes the satellite remote sensing data is difficult to interpret. In such cases the data of the terrestrial observations are used for validation of glacier characteristics along with the expert knowledge of corresponding glaciers. At present the main problem for the safety of the Georgian Military Road in the territory of Georgia is the glacial and hydrological disasters such as ice blocks falls from the Kazbegi glaciations accompanied with the debris, followed by the river bed blockage and natural dam formation, with a consequent break and pass of catastrophic mudflows. The glacial catastrophes of Kazbegi glaciers: Devdoraki, Mna, Gergeti, Abano and Chachi have great impact on Mtskheta-Stepantsminda-Larsi road safety on the territory of Georgia. The biggest catastrophes on the Georgian territory took place due to Devdoraki glacier fell in 1776, 1778, 1785, 1808, 1817, 1832. The Devdoraki glacier listed falls during those years were connected with the pulsation of the glaciers and their increase. In Kazbegi glaciation the environmental disasters occurred in 2002, 2007 and 2014 (twice). It was the result of ice layers movement. Based on the analysis, it was concluded that the creation of the May 17 and August 20, 2014 catastrophic mudflows was not connected with the glacier pulsation.

The objective of the research is to introduce the methodology for the study of Georgian glaciers on the basis of remote sensing using satellite data of high spatial resolution. The results of the numerical determination of the satellites characteristics are presented. Outputs of this study shows that the presented methodology is effective.

NMHS of Georgia closely cooperates with the European Meteorological Satellite (EUMETSAT) organization, which is reflected in regular participation in workshops organized by EUMETSAT both in Georgia and abroad. Naturally, this close cooperation will continue in the future.

The variations in glaciers are the important indicators of regional climate change. The glaciers play an important role in the regulation of water balance. In the conditions of global warming they recede and degrade that is expressed in the related changes in glacier runoff. The research of glacier melting is important for studies of sea/ocean level changes. The Caucasian glacial dimensions (area, volume, length) have been changed over the centuries.

The scientific study of glaciers in the Caucasus was started during the first half of 18th century. In the last century the terrestrial observations on glaciers were carried out. Due to the difficulties of organization and conducting of field works the received observational data sets consists from different series of various temporal duration characteristics of glaciers. The data received contain uncertainties. From another hand carrying out of such field works are expensive.

With the launch of the Earth’s satellites it was determined that satellite remote sensing is the best technology allowing to receive data with needed regularity in terms of both time and space resolution. Some uncertainties remain in the data as the observational tool is too far away from the Earth’s surface. So, the necessity for the strong quality assessment/quality control (QA/QC) remains. A lot of studies showed that the best method for investigation of glaciers is application of satellite remote sensing combined with terrestrial observations and expert knowledge of separate glaciers.

The definition of the Black Sea (BS) Sea Surface Temperature (SST) is effective by usage of satellite information. The forecast products quality is very depended on the amount and quality of initial data. The use of remote sensing promotes the necessary amount of initial data but the problem of the quality of satellite information remains that is solved by procedures of quality assurance and quality control (QA/QC). The anomalies of the satellite information are statistically analyzed on pixel and net levels. On the basis of implemented scientific researches the methodology of QA/QC of the satellite data is worked out. For these the most effective source - drifters are used is as they provide good spatial resolution of the data. In this research NOAA CLASS satellite data archive and ARGO drifter data were used. The determination of the SST real values gives possibility to run the mathematical model of marine dynamics of the Black Sea basin in operational mode. The analysis of received results revealed: The use of satellite information with drifter information is effective for determination of BS SST values; The created marine forecasting system gives reliable results that are in good accordance with reality.

The purprose of the project was the investigation of properties of individual glacier basins of the Caucaus Mountains using the TERRA Aster DEM and GLIMS database data. The adjustment of Kazbek massive glacier outlines was carried out on the basis of Aster DEM and high spatial resulution (0.6-1 m) satellite remote sensing images. The glacier characteristics where determined and compared with world glacier inventory data after outline adjustments. It is supposed that the observed difference of glacier characteristics is related with climage change.

The main objective of present work is the investigation of glaciers melting including significant ecological risks especially in connection with climate change issues. Long term satellite monitoring objectives toward the climate are: determination of the processes related with climate and glaciers interaction; detection of climate and environmental changes provided through glaciers changes; validation of global and regional climate models, sensitivity studies, climate change scenarios specification, etc. Satellite monitoring of glaciers has the well expressed potential to facilitate measurements that traditionally were performed using field techniques or ground based observations in one or several spots. High resolution space borne data allow glacier length change measurements along the entire glacier tongues, and in that way complement or even replace ground-based measurements. Using the remote sensing data it can be determined: the ice snow border; glaciers movement speed; the glacier elevation model and area of contours. The final objectives, based on the remote sensing, hydrometeorological network and glaciological observation data are: glacier monitoring technological line improvement and glacier properties determination; river Enguri pilot basin glacier runoff investigation based on determined values: creation of the Caucasian glacier models using the glacier characterizing data and glacier development forecast using these models.

The Determination of the Black Sea (BS) Surface Temperatures (SST) is the important problem of the modern oceanography for solving various applied issues. The identification of SST is the heavy problem as the observational network creation like the ground based monitoring means is expensive and such infrastructure does not exist. With establishment of the satellites the ways for the solution above problem was found. The necessary infrastructure, namely the USA and European satellites network is created. That give an impulse for installation of the platforms, buoys, drifters in oceans and seas as from one hand reception of high quality information is very important and from another hand gathering and transfer of the observational data is simplified based on the satellites. In presented work is researched in detail the most effective monitoring mean for the determination of the BS SST - remote sensing based on satellites. The quality assessment and quality control (QA/QC) Session procedures of the satellite BS SST data is created on pixel and net levels. The special numerical experiments were carried based on the marine BS scale model established in the institute of geophysics of Georgia. At the same time it is very important to assess the possibilities of the use of satellites data regarding BS SST in the operational forecasting of marine conditions. The model output – the values of the forecasted data in the knots of the regular net of BS were compared with real data of BS SST based on the statistical methodology accepted in operational practice. It is determined that using of the BS SST determined from the remote sensing in modeling significantly enhances the forecast of the Black Sea conditions. The methodology developed in the present investigation is effective for the solution of problem – namely for the determination real BS SST values.

Use of the satellite information of the Black Sea surface temperature for the purpose of creation of a      technological line of the operational forecast of the state of the Black Sea are considered.

The methodology of determination of the Black Sea surface temperature based on the use of the satellite information is presented. The quality control and quality assessment (QC/QA) of remote sensing data is investigated based on drifters information. The received results indicate effectiveness of the offered approaches given in the research.

The diagnosis of the conditions of Black Sea and forecast of its evolution is the main problem of the oceanography and environmental protection. This problem is also important for specifying of climate change scenarios that give possibility to determine correctly the strategy of the adaptation and mitigation measures. The forecasting system of marine conditions consists from the following elements: High reliability forecasting marine model; The high efficiency forecasting model of atmosphere; The initial fields for the running of model of marine dynamics. The mathematical model of marine dynamics is elaborated by Georgian scientists based on a full system of equations of ocean hydro-thermodynamics in hydrostatic approximation. This model was successfully implemented in frames of European Council FP projects ARENA and ECOOP. For the running of the model of marine dynamics the initial fields for the atmosphere components are given by calculations of numerical weather prediction limited area model - WFR model of NOAA (USA). Needed oceanographic data are given based on remote sensing monitoring. T The forecast products quality is very depended on the amount and quality of initial data. The use of remote sensing promotes the necessary amount of initial data but the problem of the quality of satellite information remains that is solved by procedures of quality assurance and quality control (QA/QC). The anomalies of the satellite information are statistically analyzed on pixel and net levels. For these the most effective source - drifters are used is as they provide good spatial resolution of the data. In this research NOAA CLASS satellite data archive and ARGO drifter data were used. The determination of the SST real values gives possibility to run the mathematical model of marine dynamics of the Black Sea basin in operational mode.

The effectiveness of the use of satellite information for the early warning of meteorological and hydrological disasters and provision of transportation safety on the Black Sea in Georgia were investigated. The research of determination of Sea Surface Temperatures by means of satellite information, verification of the obtained results based on quality control/quality assessment procedures were carried out.

The determination of the Sea Surface Temperature based on the satellite monitoring is considered. The quality control and quality assessment of remote sensing data is investigated based on the drifter information. The special BEAM programme package chosen for processing satellite data and establishing necessary data sets is presented.  

Doctoral Thesis Referee

Master Theses Supervisor

Doctoral Thesis Supervisor/Co-supervisor

Scientific editor of monographs in foreign languages

Scientific editor of a monograph in Georgian

Editor-in-Chief of a peer-reviewed or professional journal / proceedings

Review of a scientific professional journal / proceedings

Member of the editorial board of a peer-reviewed scientific or professional journal / proceedings

Participation in a project / grant funded by an international organization

Participation in a project / grant funded from the state budget

Patent authorship

Membership of the Georgian National Academy of Science or Georgian Academy of Agricultural Sciences

Membership of an international professional organization

Membership of the Conference Organizing / Program Committee

National Award / Sectoral Award, Order, Medal, etc.

Honorary title

Monograph

Handbook

Research articles in high impact factor and local Scientific Journals

Publication in Scientific Conference Proceedings Indexed in Web of Science and Scopus