Long‐term variations in summer temperatures over the Eastern Mediterranean

Abstract

[1] The inter-annual variation of the 850 hPa temperatures over the Eastern Mediterranean (EM) for July -August was analyzed for 1948-2002, using NCEP/NCAR reanalysis data. The time series of seasonal averages and the distribution of 'hot' and 'cool' days indicate the existence of three distinct warm periods. The warmest began in the mid-1990s. A long-term warming trend of 0.013 Ky À1 was found. The warming trend in July was 7 times greater than that of August, and July replaced August as the warmest month of the year. A trend of increasing extremity was also found. This was manifested in increasing seasonal standard deviation of daily temperatures, at a rate of 11% over 55 years, and in an increase in the frequency of both 'hot' and 'cool' days. These trends are also reflected in an increase in the seasonal maximum temperatures, which is 3 times greater than the increase in minimum temperatures.

Mechanisms of long‐term variations in the thermal structure of a warm lake

“…Indeed, many studies (IPCC 2007) indicate that over the past four decades, the average daily temperature has increased worldwide. In the East Mediterranean area, Saaroni et al (2003) noted that the trend is not distinct for most of the year, but in the summer, a noticeable increase of 0.06uC to 0.1uC yr 21 is recognized.…”

Is the distribution of <i>Prochlorococcus</i> and <i>Synechococcus</i> ecotypes in the Mediterranean Sea affected by global warming?

“…Genomic analysis of the clade III isolate Synechococcus sp. WH8102, indeed shows that it contains a large number of nutrient transporters but a reduced regulatory machinery (Dufresne et al, 2008;Palenik et al, 2003;Scanlan et al, 2009), strengthening the idea that members of this clade are well adapted to stable, low-nutrient environments. Moreover, this strain exhibits a well-developed cellular response to P-stress that includes the expression of genes encoding high-affinity periplasmic P-binding proteins and at least three organic phosphatases that could provide a competitive advantage for scavenging P from alternative sources when inorganic P is scarce Tetu et al, 2009).…”

“…Whilst clade IV was the dominant type over most of the year, clade I outnumbered clade IV just before the annual abundance peak of Synechococcus cell density. Genome sequences of one clade I strain (CC9311) and two clade IV strains (CC9902 and BL107) have been obtained so far (Dufresne et al, 2008;Palenik et al, 2006;Scanlan et al, 2009). The former has a slightly larger genome than the latter, and encodes a larger set of proteins involved in signal sensing (such as histidine kinases and response regulators) and metal binding (including multiple genome encoded copies of ferritin and Zn-binding metallothioneins).…”

Summer sea breeze, under suppressive synoptic forcing, in a hyper-arid city: Eilat, Israel

“…The period was chosen so that for each hour at least 10 cases of southerly winds were observed. d: temperature; n: heat stress during these months in the second half of the 1990s (Saaroni et al 2003). The wind speed also has an important relieving effect (Givoni 1991).…”