Steve Brenner

The pioneering POEM cruises (1985-1990) undoubtedly advanced our understanding of the mesoscale circulation in the SE Levantine basin, which is composed of cyclonic and anticyclonic eddies interconnected by the offshore cross-basin Mid Mediterranean Jet (MMJ). The predominant feature in the SE Levantine was shown to be the recurrent, multi-pole, anticyclonic Shikmona gyre, which was comprised of three anticyclonic eddies: one offshore Egypt, a second offshore from the shelf of Israel and Lebanon (the Shikmona eddy), and the Cyprus eddy, which was located closer to the Eratosthenes SM. For several years during the post POEM period confusion between the Shikmona eddy and the Cyprus eddy arose due to the unresolved generation mechanisms of the two. The MMJ's existence as an offshore cross-basin current was also challenged.To investigate these uncertainties, two large in-situ datasets (CTDs and XBTs) gathered in the SE Levantine from 1995-2015 (CYBO and HaiSec) were analysed and combined with the Mediterranean Sea Physics Reanalysis (https://doi.org/10.25423/CMCC/MEDSEA_MULTIYEAR_PHY_006_004_E3R1) from the Copernicus Marine Service, and with results from numerical model simulations examining the generation mechanism of the Cyprus eddy.An analysis of two decades of post-POEM dynamic height topography data showed that: a) the Cyprus eddy appearing east and southeast of the Eratosthenes SM and the Shikmona eddy appearing southeast of the Cyprus eddy are the most prominent mesoscale features; b) the centers of these two eddies exhibit significant migration with the Cyprus eddy migrating westward or south-westward from the Eratosthenes SM when the Shikmona eddy appears. The trajectories of drifters deployed offshore Israel indicated that the Shikmona eddy forms when the northward-flowing current along the Israel-Lebanese slope becomes unstable and meanders offshore. The mechanism generating the Cyprus eddy was investigated with a three-layer quasi-geostrophic model used to simulate topographic eddy formation around the Eratosthenes SM with an eastward flowing jet imposed along the western boundary of the model with varying inclinations and intensities. A single vortex mimicking the Cyprus eddy was reproduced with a secondary small-scale cyclone at its periphery. The geostrophic patterns obtained from the in-situ measurements around the Eratosthenes SM were qualitatively compared with these numerical experiments.The Modified Atlantic Water (MAW) in the SE Levantine appears as a subsurface salinity minimum based on dozens of salinity profiles gathered along the 33°E north-south cross sections extending from Cyprus to Egypt. The associated geostrophic currents computed along the same transects demonstrate that the MAW is transported: a) eastward by a strong current flowing between the southern shelf of Cyprus and the northern flank of the Cyprus eddy, b) westward by a weaker flow along the southern flank of the Cyprus eddy, and c) eastward along the Egyptian shelf and slope. Thus, the POEM group's findings describing the MMJ as a cross basin offshore current are confirmed by the MAW’s pathways based on the combined analysis of the CYBO and HaiSec in-situ data and the reanalysis, thereby providing strong evidence for its existence.

Marine zoning is a widely used spatial tool for managing ocean spaces, minimizing conflicts between uses, and maintaining ecosystem services. This review examines and profiles the use of marine zoning and its potential to support climate resilience and ecosystem services through a systematic PRISMA analysis of 121 articles. The findings highlight the importance of balancing sustainable resource use and human well-being with nature protection through well-tailored zoning objectives. The review underscores the need to expand research on underrepresented marine habitats such as seagrass and algae, which play a critical role in climate change mitigation. Additionally, it highlights the necessity of broadening the scope to consider human activities beyond fisheries, which are often the primary focus. Stakeholder engagement and public awareness are identified as crucial for effective marine zoning planning. A significant gap is noted in the integration of ecosystem services and natural capital into marine zoning research. Furthermore, despite marine zoning’s potential to address climate change challenges, the reviewed articles reveal limited attention to this topic, indicating an urgent need for further research. This review advocates for the incorporation of ecosystem service valuation and climate change considerations into marine zoning to ensure sustainable management that balances ecological preservation with human well-being.

On 15 September 2015, a convective storm yielded heavy rainfalls that caused the strongest flash flood in the last 50 years in the South Negev Desert (Israel). None of the operational forecast models predicted the event, and thus, no warning was provided. We analyzed this event using satellite, radar, and numerical weather prediction model data. We generated cloud-free climatological values on a pixel basis using Temporal Fourier Analysis on a time series of MSG geostationary satellite data. The discrepancy between the measured and climatological values was used to detect “cloud-contaminated” pixels. This simple, robust, fast, and accurate method is valuable for the early detection of convection. The first clouds were detected 30 min before they were detected by the official MSG cloud mask, 4.5 h before the radar, and 10 h before the flood reached the main road. We used the “severe storms” RGB composite and the satellite-retrieved vertical profiles of cloud top temperature–particle’s effective radius relations as indicators for the development of a severe convective storm. We also reran the model with different convective schemes, with much-improved results. Both the satellite and model-based analysis provided early warning for a very high probability of flooding a few hours before the actual flooding occurred.

An analysis of in-situ data gathered over the two decade post POEM period in the South-Eastern Levantine Basin from extensive hydrographic (CTD) campaigns and VOS XBT transects, along with data provided by the latest SeaDataCloud Mediterranean Sea Temperature and Salinity climatology (http://dx.doi.org/10.12770/3f8eaace-9f9b-4b1b-a7a4-9c55270e205a) and the Mediterranean Sea Physics Reanalysis from the Copernicus Marine Service (CMS; https://data.marine.copernicus.eu/product/MEDSEA_MULTIYEAR_PHY_006_004), have all provided insight on the dominant, coherent, meso-scale, circulation features as well as the evolution and variability of the thermohaline properties of the main water masses in this sub-basin. The most pronounced feature, the warm core Cyprus Eddy, migrates over the broad region of the Eratosthenes seamount and exhibits significant seasonal and inter-annual spatio-temporal variability. Another prominent structure is the anticyclonic Shikmona Eddy generated periodically due to instabilities of the strong northward flowing jet along the south-easternmost shelf and slope of the Levantine basin. Its evolution and co-existence with the Cyprus Eddy for periods of a few months, affects the temporal re-establishment of the Shikmona Gyre, which was first observed during the POEM cruises in the mid 1980s. The eastward flowing Mid Mediterranean Jet (MMJ) defines the northern flanks of these sub-basin scale eddies and transports the lower salinity Modified Atlantic Water (MAW) through the warmest and most saline region of the Mediterranean. Periodically the MMJ bifurcates and/or is diverted northward, along the western coast of Cyprus due to spatial fluctuations of the Cyprus Eddy. Four active periods were identified with either a dominant Cyprus Eddy only or coexisting Cyprus and Shikmona Eddies. This long term in-situ monitoring also provides an overview of the extent of the main water masses and characterizes their variability throughout the period considered. The temperature and salinity of the Levantine Surface Water (LSW) and of the subsurface MAW have increased. The Eastern Mediterranean Transient Water (EMTW) is shown to occupy the deep cavities, below the Eastern Mediterranean Deep Water (EMDW), in the vicinity of the Eratosthenes seamount while its upper boundary was lifted to shallower depths over the same period.

Wildfire simulations depend on fuel representation. Present fuel models are mainly based on the density and properties of different vegetation types. This study aims to improve the accuracy of WRF-Fire wildfire simulations, by using synthetic-aperture radar (SAR) data to estimate the fuel load and the trend of vegetation index to estimate the dryness of woody vegetation. We updated the chaparral and timber standard woody fuel classes in the WRF-Fire fuel settings. We used the ESA global above-ground biomass (AGB) based on SAR data to estimate the fuel load, and the Landsat normalized difference vegetation index (NDVI) trends of woody vegetation to estimate the fuel moisture content. These fuel sub-parameters represent the dynamic changes and spatial variability of woody fuel. We simulated two wildfires in Israel while using three different fuel models: the original 13 Anderson Fire Behavior fuel model, and two modified fuel models introducing AGB alone, and AGB and dryness. The updated fuel model (the basic fuel model plus the AGB and dryness) improved the simulation results significantly, i.e., the Jaccard similarity coefficient increased by 283% on average. Our results demonstrate the potential of combining satellite SAR data and Landsat NDVI trends to improve WRF-Fire wildfire simulations.

Local air-sea interaction over the Mediterranean may amplify the effects of climate change. This study investigates the sensitivity of simulations of two different high impact weather events to changes in the specification of sea surface temperature (SST) using a regional atmospheric model. First we assess the impact of specifying SST from two reanalysis data sets with differing spatial resolution. The simulated tropical-like cyclone (TLC) is slightly stronger in the case of the lower resolution SST which is warmer over the formation region, most notably in the maximum rainfall which is ~7% higher. The differences in the two explosive cyclone simulations are negligible, most likely due to intensification occurring mainly over land. We then test the sensitivity of the storms to a range of SST anomalies. The TLC showed a clear trend of increasing storm intensity as SST rises. These results suggest that SST plays a direct role in determining the intensity of the storm. For the explosive cyclone there is no clear trend in dynamical intensity except for the highest warming anomalies. However, the rainfall increases with the magnitude of the SST anomaly. Our results suggest that extreme weather events over the Mediterranean will become more extreme if SST increases as the climate warms, assuming that upper air conditions do not change.

Environmental risks posed by oil spills in semi-enclosed basins are more pronounced than those in the open ocean due to potential deposition along long segments of the coastlines. As a semi-enclosed sea, the Mediterranean is highly vulnerable to pollution events. Recent discoveries of major oil and natural gas reserves in the eastern Levantine basin have led to accelerated drilling, with several countries at various stages of exploration and production and others having mapped blocks for licensing, thereby significantly increasing the risks of a potential spill. Due to drilling by multiple, adjacent countries, any spills from deep water wells will be prone to cross border transport due to the highly variable winds and ocean currents. This risk is assessed through a series of simulations with an oil spill model forced with high resolution ocean currents and winds. The scenarios considered are well blowouts of several weeks duration, located within the drilling zones of each of various countries. Models such as this provide the basis for further environmental assessment and risk analysis. They also emphasize the importance of multinational cooperation to respond to and mitigate the environmental impacts which would result from a potential oil spill from any of the countries involved.

The wildland-urban interface (WUI)—the area where wildland vegetation and urban buildings intermix—is at a greater risk of fire occurrence because of extensive human activity in that area. Although satellite remote sensing has become a major tool for assessing fire damage in wildlands, it is unsuitable for WUI fire monitoring due to the low spatial resolution of the images from satellites that provide frequent information which is relevant for timely fire monitoring in WUI. Here, we take advantage of frequent (i.e., ca. daily), high-spatial-resolution (3 m) imagery acquired from a constellation of nano-satellites operated by Planet Labs (“Planet”) to assess fire damage to urban trees in the WUI of a Mediterranean city in Israel (Haifa). The fire occurred at the end of 2016, consuming ca. 17,000 of the trees (152 trees ha⁻¹) within the near-by wildland and urban parts of the city. Three vegetation indices (GNDVI, NDVI and GCC) from Planet satellite images were used to derive a burn severity map for the WUI area after applying a subpixel discrimination method to distinguish between woody and herbaceous vegetation. The produced burn severity map was successfully validated with information acquired from an extensive field survey in the WUI burnt area (overall accuracy and kappa: 87% and 0.75, respectively). Planet’s vegetation indices were calibrated using in-field tree measurements to obtain high spatial resolution maps of burned trees and consumed woody biomass in the WUI. These were used in conjunction with an ecosystem services valuation model (i-Tree) to estimate spatially-distributed and total economic loss due to damage to urban trees caused by the fire. Results show that nearly half of the urban trees were moderately and severely burned (26% and 22%, respectively). The total damage to the urban forest was estimated at ca. 41 ± 10 M USD. We conclude that using the method developed in this study with high-spatial-resolution Planet images has a great potential for WUI fire economic assessment.

Meteorological and oceanographic data collected at the head of the Gulf of Elat were used to compute the air–sea heat flux components and the heat storage in the water column, which are in turn used to estimate the heat balance of this semienclosed basin. The solar radiation was measured directly, whereas the longwave (LW) cooling and the turbulent heat fluxes (latent, LH; sensible, SH) were computed from commonly used bulk formulas. Nine formulas for LW and four formulas for LH + SH were tested for a total of 36 possible combinations. Independent estimates for the bounds on the advective heat flux through the straits and results from a one-dimensional mixed layer model provided criteria to help identify the best choice of bulk formulas for the gulf. It was concluded that the LW formula of Bignami together with the turbulent flux formulas of Kondo provide the best estimate of the heat balance of the gulf. Based on this, the annual mean evaporation is 1.6–1.8 m yr−1, with a minimum of 1 m yr−1 in (the long) summer and a maximum of 3–4 m yr−1 in (the short) winter. The increase in evaporation rate during the winter results from the instability of the atmosphere at that time when the sea surface temperature exceeds the air temperature; in the summer, when the air temperature is much higher than the sea surface temperature, evaporation nearly stops due to the atmospheric stability. This estimated evaporation rate for the gulf, which is similar for all four of the LH formulas considered, is significantly smaller than values commonly quoted in the literature. Finally, in contrast to previous studies, it is found that the advective heat flux from the Straits of Tiran is large and significant in spring, reaching an estimated value of over 125 W m−2, but its annually averaged value is only about 35–40 W m−2.