מאמרים

מרכז הידע הישראלי להערכות לשינויי אקלים
2013

Factors affecting isotopic composition of the rainwater in the Negev Desert, Israel

The study examines the δ18O of rain observed in the middle of the Negev Desert, Israel, based on seven rainstorms, associated with convective clouds resulting from midlatitude cyclones found over Trans-Jordan. The analysis is based on synoptic maps, vertical atmospheric cross sections, and air back trajectories. The rainwater sampling was done in temporal scale of hours. Four known factors were addressed here: the temperature effect, the amount effect, and two geographical effects: the marine an
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2011

Assessment of climate change impact on hydrological extremes in two source regions of the Nile River Basin

The potential impact of climate change was investigated on the hydrological extremes of Nyando River and Lake Tana catchments, which are located in two source regions of the Nile River basin. Climate change scenarios were developed for rainfall and potential evapotranspiration (ETo), considering 17 General Circulation Model (GCM) simulations to better understand the range of possible future change. They were constructed by transferring the extracted climate change signals to the observed series using a frequency perturbation downscaling approach, which accounts for the changes in rainfall extremes. Projected changes under two future SRES emission scenarios A1B and B1 for the 2050s were considered. Two conceptual hydrological models were calibrated and used for the impact assessment. Their difference in simulating the flows under future climate scenarios was also investigated. The results reveal increasing mean runoff and extreme peak flows for Nyando catchment for the 2050s while unclear trend is observed for Lake Tana catchment for mean volumes and high/low flows. The hydrological models for Lake Tana catchment, however, performed better in simulating the hydrological regimes than for Nyando, which obviously also induces a difference in the reliability of the extreme future projections for both catchments. The unclear impact result for Lake Tana catchment implies that the GCM uncertainty is more important for explaining the unclear trend than the hydrological models uncertainty. Nevertheless, to have a better understanding of future impact, hydrological models need to be verified for their credibility of simulating extreme flows.
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2011

Climatological relationships among the moisture budget components and rainfall amounts over the Mediterranean based on a super-high-resolution climate model

The present seasonal (October-March) precipitation simulated from the 20 km GCM showed a quite reasonable agreement with the CRU. The seasonal area mean precipitation and evaporation are 1.85 mm/d and 2.44 mm/d, respectively. The largest two precipitation categories contribute over 50% of the total seasonal rainfall. The evaporation varies positively with the precipitation for all precipitation categories. Also, the relatively high mean recycling ratio (55%) indicates that the local Med evaporation has a central role in the local precipitation. Another important finding is that the decreasing trend of recycling ratio with the rising of the precipitation category implies that the outside moisture inflow role increases with the increase of the precipitation category. For all the precipitation categories, the total outflow is larger than the total inflow, indicating that the Med area is an important source of moisture. Individual boundary moisture flux shows that the main moisture comes from the west boundary and contributes 59% of the total inflow, while the main outflow is through east boundary and is responsible for 46% of total outflow. Analysis of monthly precipitation indicates that the October and November have the two largest amount of precipitation over the research region. The moisture budget study separated for the east and the west Med shows that the area mean precipitation for the east and the west Med are 2.14 and 2.29 mm/d, while the evaporation are 4.48 and 3.59 mm/d. The plausible reason for the differences between these two basins has been discussed. The moisture supplies to the east Med is mainly from the west boundary, while for the west Mediterranean, the north boundary inflow also plays an important role along with the west boundary. The future moisture budget components over Med suggest that the precipitation is decreasing from 1.85 to 1.62 mm/d and the evaporation is increasing from 2.44 to 2.56 mm/d between current and future. Another finding is that the largest precipitation number of months decreases from 12% to only 6% of the total number of months, while the intensity of the precipitation in this category enhances in the future.
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2010

Monthly rainfall changes in Central and Western Mediterranean basins, at the end of the 20th and beginning of the 21st centuries

Changes in the statistical distribution of rainfall amounts have been studied in four Mediterranean regions: the French and Spanish Mediterranean coasts, Sardinia Island, and the Calabrian region, in Italy. The largest precipitation series (from 70 to 150 years) in these zones have been collected and studied at yearly and monthly time scales by means of different parametric and nonparametric techniques. Nonparametric procedures have focussed on continuous time series changes, while possible changes at the end of the 20th century have been studied developing a parametric method. Among the results obtained, the 1984/1985 to 1994/1995 and 1994/1995 to 2004/2005 decades have been revealed as some of the driest ones since data are available in central and western Mediterranean. Despite that, such a finding is not always accompanied with a trend in the entire rainfall series. On the one hand, the low precipitation amounts detected in Central Mediterranean are caused in its major contribution by a diminution of the winter rainfall. On the other hand, a diminution of the spring and winter rainfall is the cause of the driest records since data are available in Western Mediterranean. Possible relations between the dry records and seasonal SLP-based indexes have been studied. The seasonal configurations of the North Atlantic Oscillation (NAO) have been calculated and their time series have provided a good perspective on the evolution of the most contributive synoptic patterns to climate variability at the region. The high frequency of positive seasonal phases of winter, spring and autumn NAO at the end of the 20th century and beginning of the 21st have been found as possible dynamic mechanism causing the last decades dryness. Moreover, moving correlations suggest a strengthening in the correlation between those seasonal NAOs and precipitation anomalies in Central and Western Mediterranean.
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2010

Links between the rainfall regime in Israel and location and intensity of Cyprus lows

The interannual variations and the spatial distribution of rainfall in the Mediterranean and semi-arid regions of Israel are analysed with respect to variations in the occurrence of the typical synoptic systems of the Eastern Mediterranean. The synoptic analysis is based on a daily, semi-objective synoptic classification (Alpert et al., 2004a). The study covers the months November–March, in which 90% of the annual rainfall is obtained, mostly resulting from Cyprus lows. The interannual variations of the rainfall are well explained by the synoptic types, and the occurrences of Cyprus lows are highly correlated with the rainfall. It was found that the daily and seasonal rainfall are highly dependent on the depth of the cyclone. Moreover, deep lows are more effective for the mountainous regions, due both to the enhanced orographic effect and to the fact that stronger winds, associated with deep lows, are more efficient in transporting rain-producing clouds from the Mediterranean Sea inland. The location of the cyclone determines the spatial distribution of the rain it produces over Israel. The cyclones located east of Cyprus were found productive mainly for the southern parts of the study region, while those located to the west and north of Israel were found productive for the north of the country. The high sensitivity of the rainfall to the location of the surface cyclones emphasizes the major role that lower level moisture transport plays in rain formation.
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2003

Late Holocene climates of the Near East deduced from Dead Sea level variations and modern regional winter rainfall

The Dead Sea is a terminal lake of one of the largest hydrological systems in the Levant and may thus be viewed as a large rain gauge for the region. Variations of its level are indicative of the climate variations in the region. Here, we present the decadal- to centennial-resolution Holocene lake-level curve of the Dead Sea. Then we determine the regional hydroclimatology that affected level variations. To achieve this goal we compare modern natural lake-level variations and instrumental rainfall records and quantify the hydrology relative to lake-level rise, fall, or stability. To quantify that relationship under natural conditions, rainfall data pre-dating the artificial Dead Sea level drop since the 1960s are used. In this respect, Jerusalem station offers the longest uninterrupted pre-1960s rainfall record and Jerusalem rains serve as an adequate proxy for the Dead Sea headwaters rainfall. Principal component analysis indicates that temporal variations of annual precipitation in all stations in Israel north of the current 200 mm yr−1 average isohyet during 1940–1990 are largely synchronous and in phase (∼70% of the total variance explained by PC1). This station also represents well northern Jordan and the area all the way to Beirut, Lebanon, especially during extreme drought and wet spells. We (a) determine the modern, and propose the past regional hydrology and Eastern Mediterranean (EM) climatology that affected the severity and length of droughts/wet spells associated with multiyear episodes of Dead Sea level falls/rises and (b) determine that EM cyclone tracks were different in average number and latitude in wet and dry years in Jerusalem. The mean composite sea level pressure and 500-mb height anomalies indicate that the potential causes for wet and dry episodes span the entire EM and are rooted in the larger-scale northern hemisphere atmospheric circulation. We also identified remarkably close association (within radiocarbon resolution) between climatic changes in the Levant, reflected by level changes, and culture shifts in this region.
מידע נוסף

מאמרים ופרסומים אחרונים

מרכז הידע הישראלי להערכות לשינויי אקלים
2015

Periodic Report Summary 1 - DYNAMIC (DYNamic feedbacks of climate impacts on current Adaptation and Mitigation Investment Choice)

The DYNAMIC (DYNamic feedbacks of climate impacts on current Adaptation and Mitigation Investment Choice) project proposes a novel framework to evaluate the economic consequences of climate change impacts and related policy responses.
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2015

בחינת תרומת קבוצות סוציו אקונומיות בישראל לפליטות גזי חממה מצריכת מזון ביתי

לייצור המזון, במיוחד בחקלאות התעשייתית, נודעת השפעה ממשית על היקף פליטות גזי חממה באופן ישיר או עקיף. גזי חממה אלו נוצרים בכל שלבי מחזור החיים של המזון, החל משלב החקלאות ותשומותיו, דרך הייצור, הפצה, קירור, קמעונאות, הכנת המזון בבית וכלה בסילוק הפסולת.למעשה, בעוד שבמחקרים השונים קיימת הסכמה על כך שפליטות גזי חממה מייצור המזון וצריכתו מהוות חלק משמעותי מפליטות גזי החממה בעולם, המחלוקת המחקרית נסובה סביב הערכת היקף הפליטות. לדוגמא, לפי דוח של האו"ם מ- 2014 14.5% מפליטות גזי החממה כתוצאה מפעילו
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2014

Explaining Extreme Weather Events of 2013 from a Climate Perspective

The annual Bulletin of the American Meteorological Society (BAMS) special issue on the attribution of last year’s extreme weather events is published today. This year’s issue “explaining extreme events of 2013 – from a climate perspective” includes two papers led by researchers from our climateprediction. This is a highly-cited and influential annual publication coined in 2012 asking whether and to what extent anthropogenic climate change altered the risk of major extreme weather events of the p
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2014

Lima call for climate action- Decision

Climate Action & UNEP delivered their fifth annual Sustainable Innovation Forum on December 9 in Lima. This year’s event brought together close to 500 leaders from key United Nations bodies, governments, international & regional companies and leading non-governmental organisations (NGO's).
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2012

Climate Prediction for Adaptation: Who needs what?

The role of short- and long-term climate predictions in determining the success of adaptation to climate change is investigated. A simple theoretical model that captures the relationship between adaptive performance, decision structure, and prediction accuracy at different temporal scales is developed, and its implications deduced. It is shown that users who face high adjustment costs (i.e. are inflexible) depend more heavily on accurate long-term predictions than those who are able to adjust
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2012

UK climate change risk assessment: government report

The Government published the UK Climate Change Risk Assessment (CCRA) on 25 January 2012, the first assessment of its kind for the UK and the first in a 5 year cycle. It sets out the main priorities for adaptation in the UK under 5 key themes identified in the CCRA 2012 Evidence Report - Agriculture and Forestry; Business, industries and Services; Health and Wellbeing; Natural Environment and Buildings and Infrastructure - and describes the policy context, and action already in place to tackle
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2011

2011 Bonn Declaration of Mayors

This declaration is the outcome document of the Mayors Adaptation Forum, which forms the Mayors segment of the Resilient Cities 2011 congress. It highlights the need to build resilience to disasters as a critical issue. It also signals the need to take appropriate action to build local capacities in reducing risk to disasters including those exacerbated by climate change.
The declaration advocates for the implementation of the following: (i) mainstreaming new adaptation and resilience standard
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2011

A double-resolution transient RCM climate change

A double-resolution regional experiment on hydrodynamic simulation of climate over the eastern Mediterranean (EM) region was performed using an International Center for Theoretical Physics, Trieste RegCM3 model. The RegCM3 was driven from the lateral boundaries by the data from the ECHAM5/MPI-OM global climate simulation performed at the MPI-M, Hamburg and based on the A1B IPCC scenario of greenhouse gases emission. Two simulation runs for the time period 1960-2060, employing spatial resolutions
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2011

Climate Change Adaptation and Real Option Evaluation: A Case Study in Campeche, Mexico

This report illustrates the application of a (relatively) new method to guide decision making under high (and unknowable) levels of uncertainty. The approach allows for the identification of robust policy options that are economically beneficial under different scenarios and varying levels uncertainty. Option value techniques are commonly employed in the finance literature to identify investment decisions that are resilient across a spectrum of outcomes. The methods are technically advanced
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2011

ipcc summary for policymakers

The Working Group III Special Report on Renewa
ble Energy Sources and Climate Change
Mitigation (SRREN) presents an assessment of th
e literature on the scientific, technological,
environmental, economic and social aspects of
the contribution of six renewable energy (RE)
sources to the mitigation of climate change. It is
intended to provide policy relevant information to
governments, intergovernmental processes and ot
her interested parties. This Summary for
Policymakers provides an ov
מידע נוסף
מרכז הידע הישראלי להערכות לשינויי אקלים
2008

Climate change- vulnerability and adaptation indicators

The purpose of this Technical Paper is to rehearse some fundamental concepts surrounding the
development and delineation of adaptation indicators. It builds upon the outputs of an Expert meeting
on climate change vulnerability and adaptation indicators (Budapest, September 2008) and on the
contents of a Background Paper that was prepared for the meeting.
מידע נוסף
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