scholarly journals Sensitivity of Modeled Precipitation to Sea Surface Temperature in Regions with Complex Topography and Coastlines: A Case Study for the Mediterranean

2014 ◽  
Vol 15 (6) ◽  
pp. 2370-2396 ◽  
Author(s):  
Alfonso Senatore ◽  
Giuseppe Mendicino ◽  
Hans Richard Knoche ◽  
Harald Kunstmann
Keyword(s):  
Lower Boundary ◽  
Wrf Model ◽  
Specific Class ◽  
Lower Boundary Condition ◽  
Orographic Effects ◽  
Mountain Ranges ◽  
Precipitation Patterns ◽  
The North ◽  
Data Points ◽  
The Mediterranean

Abstract An analysis of the effects of SST representation on precipitation in long-term continuous simulations was carried out for the Mediterranean peninsula of Calabria, Italy, which is characterized by complex coastlines and orography. A parameterization analysis was performed to find an optimal model configuration, using a method where SST fields are directly ingested from NCEP datasets into the Weather Research and Forecasting (WRF) Model lower boundary condition files. The results of the optimal configuration were used for a comparison with recorded precipitation patterns for a very wet period (from November 2008 to January 2009), adopting several interpolation options available in the WRF Preprocessing System. An additional comparison was made against a uniform variation of the original SST fields by ε = ±0.5 K. It was found that the interpolation options mainly affect near-coastline SSTs, where methods requiring fewer source data points have several advantages. Effects of SST representation on precipitation, accumulated over the whole 3-month period, are generally lower than ±2%, but a specific class of events (synoptic situations) with strong differences in precipitation patterns was identified. These events are connected to pressure systems moving from the African coast to the north and approaching the Sicilian and Calabrian coastlines. Two of these events, which occurred on 27–29 December 2008 and 9 January 2009, were analyzed in detail, highlighting that small variations of SST values induce slight shifts in the paths of the weather fronts. These slight shifts are important enough to determine whether or not wet air masses can reach the mountain ranges close to the coast, where rainfall intensity is enhanced by orographic effects.

Response to the Summer of 2003 Mediterranean SST Anomalies over Europe and Africa

2006 ◽  
Vol 19 (20) ◽  
pp. 5439-5454 ◽  
Author(s):  
Thomas Jung ◽  
Laura Ferranti ◽  
Adrian M. Tompkins
Keyword(s):  
Mediterranean Sea ◽  
Atmospheric Circulation ◽  
Lower Boundary ◽  
Western Mediterranean ◽  
Minor Role ◽  
Sensitivity Experiment ◽  
Lower Boundary Condition ◽  
The Mediterranean ◽  
Ecmwf Model ◽  
Sst Anomalies

Abstract The sensitivity of the atmospheric circulation to the warm Mediterranean sea surface temperature (SST) anomalies observed during the summer of 2003 (July and August) is studied using the European Centre for Medium-Range Weather Forecasts (ECMWF) model. A control integration imposes climatological Mediterranean SSTs as a lower boundary condition. The first sensitivity experiment uniformly increases these Mediterranean SSTs by 2 K, the approximate mean observed in the 2003 summer season. A second experiment then investigates the additional impact of the SST distribution by imposing the observed SST summer anomaly. The response of the atmospheric circulation in the European area shows some resemblance to the observed anomaly. The weakness of this response suggests, however, that the warm Mediterranean played a minor role, if any, in maintaining the anomalous atmospheric circulation as observed in the summer of 2003. Increasing SST in the Mediterranean locally leads to an increase in precipitation, particularly in the western Mediterranean. Furthermore, significantly increased Sahelian rainfall is simulated, deriving from enhanced evaporation in the Mediterranean Sea. In the ECMWF model the anomalously high moisture is advected by the climatological Harmattan and Etesian winds, where enhanced moisture flux convergence leads to more precipitation. The associated diabatic heating leads to a reduction of the African easterly jet strength. A similar Sahelian response has been previously documented using a different atmospheric model, increasing confidence in the robustness of the result. Finally, the results are discussed in the context of the seasonal predictability of European and African climate.

scholarly journals The flickering connectivity system of the north Andean páramos

2019 ◽  
Author(s):  
Suzette G.A. Flantua ◽  
Aaron O’Dea ◽  
Renske E. Onstein ◽  
Henry Hooghiemstra
Keyword(s):  
Lower Boundary ◽  
Habitat Connectivity ◽  
Pollen Record ◽  
Climate Conditions ◽  
Northern Andes ◽  
Climate Fluctuations ◽  
Mountain Ranges ◽  
Biogeographic Patterns ◽  
The North ◽  
Pleistocene Climate

ABSTRACT AND KEYWORDSAimTo quantify the effect of Pleistocene climate fluctuations on habitat connectivity across páramos in the Neotropics.LocationThe Northern AndesMethodsThe unique páramos habitat underwent dynamic shifts in elevation in response to changing climate conditions during the Pleistocene. The lower boundary of the páramos is defined by the upper forest line, which is known to be highly responsive to temperature. Here we reconstruct the extent and connectivity of páramos over the last 1 million years (Myr) by reconstructing the UFL from the long fossil pollen record of Funza09, Colombia, and applying it to spatial mapping on modern topographies across the Northern Andes for 752 time slices. Data provide an estimate of how often and for how long different elevations were occupied by páramos and estimates their connectivity to provide insights into the role of topography in biogeographic patterns of páramos.ResultsOur findings show that connectivity amongst páramos of the Northern Andes was highly dynamic, both within and across mountain ranges. Connectivity amongst páramos peaked during extreme glacial periods but intermediate cool stadials and mild interstadials dominated the climate system. These variable degrees of connectivity through time result in what we term the ‘flickering connectivity system’. We provide a visualization (video) to showcase this phenomenon. Patterns of connectivity in the Northern Andes contradict patterns observed in other mountain ranges of differing topographies.Main conclusionsPleistocene climate change was the driver of significant elevational and spatial shifts in páramos causing dynamic changes in habitat connectivity across and within all mountain ranges. Some generalities emerge, including the fact that connectivity was greatest during the most ephemeral of times. However, the timing, duration and degree of connectivity varied substantially among mountain ranges depending on their topographic configuration. The flickering connectivity system of the páramos uncovers the dynamic settings in which evolutionary radiations shaped the most diverse alpine biome on Earth.

Spatial Distribution of Pre-Warm Front Rainfall in the Mediterranean Area

1988 ◽  
Vol 19 (1) ◽  
pp. 53-64 ◽  
Author(s):  
C. Corradini ◽  
F. Melone
Keyword(s):  
Mediterranean Area ◽  
Compact Structure ◽  
Large Variability ◽  
Air Mass ◽  
Orographic Effects ◽  
Warm Front ◽  
Average Rainfall ◽  
Convective Motions ◽  
Rainfall Type ◽  
The Mediterranean

Evidence is given of the distribution of pre-warm front rainfall at the meso-γ scale, together with a discussion of the main mechanisms producing this variability. An inland region in the Mediterranean area is considered. The selected rainfall type is commonly considered the most regular inasmuch as it is usually unaffected by extended convective motions. Despite this, within a storm a large variability in space was observed. For 90% of measurements, the typical deviations from the area-average total depth ranged from - 40 to 60 % and the storm ensemble-average rainfall rate over an hilly zone was 60 % greater than that in a contiguous low-land zone generally placed upwind. This variability is largely explained in terms of forced uplift of air mass over an envelope type orography. For a few storms smaller orographic effects were found in locations influenced by an orography with higher slopes and elevations. This feature is ascribed to the compact structure of these mountains which probably determines a deflection of air mass in the boundary layer. The importance of this type of analysis in the hydrological practice is also emphasized.

scholarly journals Impact of air–sea coupling on the climate change signal over the Iberian Peninsula

2021 ◽  
Author(s):  
Alba de la Vara ◽  
William Cabos ◽  
Dmitry V. Sein ◽  
Claas Teichmann ◽  
Daniela Jacob
Keyword(s):  
Climate Change ◽  
Iberian Peninsula ◽  
Mediterranean Sea ◽  
Large Scale ◽  
Regional Distribution ◽  
Coupled Model ◽  
Climate Change Signal ◽  
The North ◽  
The Mediterranean ◽  
The Impact

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.

scholarly journals Polychaete Diversity Related to Different Mesophotic Bioconstructions along the Southeastern Italian Coast

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 239
Author(s):  
Maria Flavia Gravina ◽  
Cataldo Pierri ◽  
Maria Mercurio ◽  
Carlotta Nonnis Marzano ◽  
Adriana Giangrande
Keyword(s):  
Circulation Pattern ◽  
High Turnover ◽  
The North ◽  
Α Diversity ◽  
Biological Determinants ◽  
High Species Richness ◽  
The Mediterranean ◽  
Current Circulation ◽  
Italian Coast

In the different mesophotic bioconstructions recently found along the Southeastern Italian coast, polychaetes have been proved to show high species richness and diversity, hitherto never investigated. In the present study, the species composition and functional role of polychaete assemblages were analysed; the updated key to identification of the Mediterranean species of genus Eunice was presented and some taxonomic issues were also discussed. On the total of 70 species Serpulidae and Eunicida were the dominant polychaetes. Facing similar levels of α-diversity, the polychaete assemblages showed a high turnover of species along the north-south gradient, clearly according to the current circulation pattern, as well as to the different bioconstructors as biological determinants. Indeed, Serpulidae were dominant on the mesophotic bioconstructions primarily formed by the deep-sea oyster Neopycnodonte cochlear, while the Eunicida prevailed on the mesophotic bioconstructions mainly built by scleractinians. Lastly, the record of Eunice dubitata was the first for the Mediterranean and Italian fauna and proved this species to be characteristic of mesophotic bioconstructions.

scholarly journals THE MERCURIO GUNFLINTS: A TECHNO-TYPOLOGICAL AND CULTURAL ASSESSMENT

2016 ◽  
Vol 96 ◽  
pp. 363-389 ◽  
Author(s):  
Paolo Biagi ◽  
Elisabetta Starnini ◽  
Carlo Beltrame
Keyword(s):  
Nineteenth Century ◽  
Northern Italy ◽  
Size And Shape ◽  
Manufacturing Technique ◽  
The North ◽  
Major Significance ◽  
Cultural Assessment ◽  
The Mediterranean ◽  
Napoleonic Era ◽  
Small Finds

The discovery of the wreck of the brig Mercurio, which sank in 1812 in the waters of the north Adriatic, is of major significance for the study of Italic Kingdom vessels from the Napoleonic era. The underwater excavations carried out in 2004–11 led to the recovery of many small finds, among which are several gunflints of different size and shape. The Mercurio gunflints were produced mainly from blades using a technique in use in Britain and France, but also in the workshops of the Lessini Hills around Ceredo (Verona province, northern Italy). We suggest that the flint employed for their manufacture probably came from Monte Baldo, in the Trentino, or perhaps from the River Tagliamento, in Friuli. We can exclude the possibility that the specimens recovered from the shipwreck were made from French flint because of the typically north Italian manufacturing technique and the character of the grey Treveti-derived flint. Given the complexity of the period during which the Grado (or Pirano) battle took place, the study of even such small items can contribute to a better interpretation of the dramatic events that characterised the beginning of the nineteenth century in that part of the Mediterranean.

Examining the impacts of Great Lakes’ temperature perturbations on simulated precipitation in the northeastern United States

2021 ◽  
Author(s):  
Janel Hanrahan ◽  
Jessica Langlois ◽  
Lauren Cornell ◽  
Huanping Huang ◽  
Jonathan Winter ◽  
...  
Keyword(s):  
Great Lakes ◽  
New England ◽  
General Circulation ◽  
Lower Boundary ◽  
Historical Period ◽  
Spatial And Temporal Variability ◽  
Lake Surface ◽  
The North ◽  
Surface Temperatures ◽  
Simulated Precipitation

AbstractMost inland water bodies are not resolved by General Circulation Models, requiring that lake surface temperatures be estimated. Given the large spatial and temporal variability of the North American Great Lakes’ surface temperatures, such estimations can introduce errors when used as lower boundary conditions for dynamical downscaling. Lake surface temperatures (LSTs) influence moisture and heat fluxes, thus impacting precipitation within the immediate region and potentially in regions downwind of the lakes. For the present study, the Advanced Research Weather Research and Forecasting Model (WRF-ARW) was used to simulate precipitation over six New England states during a five-year historical period. The model simulation was repeated with perturbed LSTs, ranging from 10°C below to 10°C above baseline values obtained from reanalysis data, to determine whether the inclusion of erroneous LST values impact simulated precipitation and synoptic-scale features. Results show that simulated precipitation in New England is statistically correlated with LST perturbations, but this region falls on a wet-dry line of a larger bimodal distribution. Wetter conditions occur to the north and drier conditions to the south with increasing LSTs, particularly during the warm season. The precipitation differences coincide with large-scale anomalous temperature, pressure, and moisture patterns. Care must therefore be taken to ensure reasonably accurate Great Lakes’ surface temperatures when simulating precipitation, especially in southeastern Canada, Maine, and the Mid-Atlantic region.

Sign in / Sign up

Export Citation Format

Share Document