Tag Archive: world climate

Aug
14
2010

Russian heatwave and Pakistani floods.

Categories:

by

August 14, 2010

English Version

We’ve all heard about the great Russian heat wave this summer. Some 15.000 people died because of the toxic plumes produced by the forest fires around Moscow area because of the unusual high temperatures of over 30 Celsius since late June. The real question is what caused that extreme situation in Russian and how that is connected with the monsoon period in Pakistan.

First things first, in meteorology there is a term which defines  an upper-level river of air, between the altitudes of about 10,000 – 12,000 meters ,which is called jet stream. During summer time that jet stream might be a weaker that blows across northern Europe coming from the poles and a strong southern “subtropical” jet that blows across southern Europe. The first one brings all the rain at the North of Europe including Russia, while the second brings all the heat from Africa disallowing any precipitation whatsoever. The polar jet stream also acts as the boundary between cold, Arctic air, and warm tropical air. If the polar jet stream shifts to the north of its usual location, areas just to its south will be much hotter and drier than normal.

In July 2010, a remarkably strong polar jet stream developed over northern Europe. This jet curved far to the north of Moscow, then plunged southwards towards Pakistan. This allowed hot air to travel northwards over most of European Russia, and prevented rainy systems over that area. These rain-bearing low pressure systems passed far to the north of European Russia, then dove unusually far to the south, into northern Pakistan. The heavy rains from these lows combined with Pakistan’s usual summer monsoon rains were enough for Pakistan to face its worst floods in recent history.

According to recent reports unusual sea surface temperature patterns could be the primary reason for this unusual behaviour of the jet streams. Scientists found that during the summer of 2003, exceptionally high sea surface temperatures of 4°C  above average over the Mediterranean Sea, combined with unusually warm SSTs in the northern portion of the North Atlantic Ocean near the Arctic, combined to shift the jet stream to the north over Western Europe and create the heat wave of 2003. I expect that the current SST pattern over the ocean regions surrounding Europe played a key role in shifting the jet stream to create the heat wave of 2010. Finally in my opinion, human caused climate change also may have played a role, especially since great heat wave episodes seems to be more frequent the past 10 years.

Ελληνικά

Το φετινό εφιαλτικό καλοκαίρι για τους Ρώσσους θα το θυμούνται για παρα πολύ καιρό. Θερμοκρασίες ρεκορ για πολλές τους πόλεις, με την μέση τιμή Ιουλίου να μην έχει πέσει κάτω απο τους 30 Κελσίου, ουσιαστικά θυμίζει Ελληνικό παρα Ρωσσικό καλοκαίρι. Όσο και εαν φαίνεται παράξενο υπάρχει επιστημονική απάντηση για αυτό το φαινόμενο, αν και ακραίο, το οποίο μάλιστα καταλήγει στην δεύτερη τραγωδία του Αυγούστου και τους νεκρούς του Πακιστάν απο τις μεγαλύτερες πλημμύρες όλων των εποχών στη χώρα.

Αρχικά να τονίσω 2 μετεωρολογικά δεδομένα τα οποία θα τα χρειαστούμε για την περαιτέρω ανάλυση και κατανόηση των φαινομένων της κυκλοφορίας της ατμόσφαιρας.  Το καλοκαίρι έχουμε ουσιαστικά πάνω απο την Ευρώπη τον ασθενή πολικό αεροχείμαρρο (polar jet stream) ο οποίος φυσάει στην Βόρεια Ευρώπη ουσιαστικά, χαμηλώνοντας την θερμοκρασία και φέρνοντας αρκετή βροχή, και τον υποτροπικό αεροχείμαρρο (subtropical jet stream) ο οποίος φυσάει στη Νότια Ευρώπη και φέρνει ουσιαστικά την ζέστη απο τους τροπικούς, ρίχνει την υγρασία και φυσικά αποτρέπει τις πολλές βροχοπτώσεις. Ο πολικός επίσης ενεργεί και σαν σύνορο μεταξύ του κρύου αρκτικού αέρα και του ζεστού τροπικού. Τυγχόν μετατόπιση του πολικού αεροχειμάρρου σε βορειότερη θέση απο αυτή που βρίσκεται συνήθως έχει σαν αποτέλεσμα την άνοδο και του ζεστού υποτροπικού, με συνέπειες την άνοδο της θερμοκρασίας και της μείωσης της υγρασίας των περιοχών που βρίσκονται κάτω απο την επίδραση του.

Αυτό ακριβώς το φαινόμενο, της μετατόπισης του αεροχειμάρρου βορειότερα της Ευρώπης είχαμε τον Ιούλιο του 2010. Αυτός ο ιδιαίτερα ισχυρός πολικός αεροχείμαρρος παρέκαμψε την Ευρωπαική Ρωσσία και στη συνέχεια βυθίστηκε απότομα προς το Πακιστάν.  Αυτό επέτρεψε ζεστό αέρα να ταξιδέψει προς τα βόρεια κατά το μεγαλύτερο μέρος της ευρωπαϊκής Ρωσίας, και εμπόδισε βροχερά συστήματα επί του εν λόγω τομέα. Οι βροχές που φέρουν αυτά τα  συστήματα χαμηλής πίεσης πέρασε μακριά, στα βόρεια της ευρωπαϊκής Ρωσίας, και στη συνέχεια έφτασε ασυνήθιστα μακριά προς τα νότια, στο βόρειο Πακιστάν. Οι έντονες βροχοπτώσεις από τα εν λόγω χαμηλά σε συνδυασμό με τις  βροχές τις εποχής των μουσώνων του Πακιστάν ήταν αρκετά για να αντιμετωπίσει η χώρα τις χειρότερες πλημμύρες  στην πρόσφατη ιστορία της.

Σύμφωνα με πρόσφατες αναφορές ασυνήθιστη θαλάσσια θερμοκρασία  θα μπορούσε να είναι ο κύριος λόγος για αυτή την περίεργη συμπεριφορά του αεροχειμάρρου. Οι επιστήμονες διαπίστωσαν ότι κατά τη διάρκεια του καλοκαιριού του 2003, εξαιρετικά υψηλές θερμοκρασίες της θάλασσας της Μεσογείου ( 4 ° C πάνω από το μέσο όρο), σε συνδυασμό με τις ασυνήθιστα θερμές θερμοκρασίες θάλασσας στο βόρειο τμήμα του Βόρειου Ατλαντικού Ωκεανού κοντά στην Αρκτική, είχε αποτέλεσμα την μετατόπιση του αεροχειμάρρου πάνω από τη βόρεια Δυτική Ευρώπη προκαλώντας το κύμα καύσωνα του 2003.  Ανάλογη συμπεριφορά των θαλασσών που περιβάλλουν την Ευρώπη και οι οποίες έχουν θερμανθεί πολύ προκάλεσε και το 2010 την μετατόπιση του πολικού σε περιοχές που δεν μπορούσε να επηρρεάσει την Ρωσική ενδοχώρα.

VN:F [1.9.13_1145]
Rating: 0.0/10 (0 votes cast)
VN:F [1.9.13_1145]
Rating: 0 (from 0 votes)

Tags: , , , ,

Permanent link to this article: http://www.euaclan.org/2010/08/russian-heatwave-and-pakistani-floods/

Aug
09
2010

Over 15,000 likely dead in Russian heat wave.

Categories:

by

August 9, 2010

The Great Russian Heat Wave of 2010 brought temperatures of 37°C (99°F) to Moscow today, and smog and smoke from wildfires blanketed the city for a sixth straight day. Air pollution levels were 2 – 3 times the maximum safe level today, and peaked on Saturday, when when carbon monoxide hit 6.5 times the safe level. The death toll from heat and air pollution increased to approximately 330 people per day in Moscow in recent days, according to the head of the Moscow health department. Yevgenia Smirnova, an official from the Moscow registry office, said excess deaths in Moscow in July averaged 155 per day, compared to 2009. The heat wave began on June 27. These grim statistics suggest that in Moscow alone, the Great Russian Heat Wave of 2010 has likely killed at least 7,000 people so far. A plot of the departure of July 2010 temperatures from average (Figure 1) shows that the area of Russia experiencing incredible heat is vast, and that regions southeast of Moscow have the hottest, relative to average. Moscow is the largest city in Russia, with a population just over ten million, but there are several other major cities in the heat wave region. These include Saint Petersburg, Russia’s 2nd most populous city (4.6 million), and Nizhny Novgorod, Russia’s 5th most populous city (1.3 million people.) Thus, the Russian population affected by extreme heat is at least double the population of Moscow, and the death toll in Russia from the 2010 heat wave is probably at least 15,000, and may be much higher. The only comparable heat wave in European history occurred in 2003, and killed an estimated 40,000 – 50,000 people, mostly in France and Italy. While the temperatures in that heat wave were not as extreme as the Russian heat wave, the nighttime low temperatures in the 2003 heat wave were considerably higher. This tends to add to heat stress and causes a higher death toll. I expect that by the time the Great Russian Heat Wave of 2010 is over, it may rival the 2003 European heat wave as the deadliest heat wave in world history.


Figure 1. A comparison of August temperatures, the peak of the great European heat wave of 2003 (left) with July temperatures from the Great Russian Heat Wave of 2010 (right) reveals that this year’s heat wave is more intense and covers a wider area of Europe. Image credit:NOAA/ESRL.

Worst Russian heat wave in 1,000 years of history
The temperature at Moscow’s Domodedovo Airport hit 99°F (37°C) today. Prior to this year, the hottest temperature in Moscow’s history was 37.2°C (99°F), set in August 1920. The Moscow Observatory has now matched or exceeded this 1920 all-time record five times in the past two weeks. Temperatures the past 27 days in a row have exceeded 30°C in Moscow. Alexander Frolov, head of Russia’s weather service, said in a statement today, “Our ancestors haven’t observed or registered a heat like that within 1,000 years. This phenomenon is absolutely unique.” There is some slight relief in sight–the latest forecast for Moscow calls for high temperatures of 31 – 33°C (88 – 91 °F) Wednesday though Sunday.

Belarus records its hottest temperature in history for the second day in a row
The Russian heat wave has also affected the neighboring nations of Ukraine and Belarus. All three nations have recorded their hottest temperatures in history over the past few weeks. Belarus, on the western border of Russia, recorded its hottest temperature in history on Saturday, August 7, when the mercury hit 38.9°C (102°F) in Gomel. This broke the all-time record for extreme heat set just one day before, the 38.7°C (101.7°F) recorded in Gorky. Prior to 2010, the hottest temperature ever recorded in Belarus was the 38.0°C (100.4°F) in Vasiliyevichy on Aug. 20, 1946. As I described in detail in Saturday’s post, Belarus’ new all-time extreme heat record gives the year 2010 the most national extreme heat records for a single year–seventeen. These nations comprise 19% of the total land area of Earth. This is the largest area of Earth’s surface to experience all-time record high temperatures in any single year in the historical record. Looking back at the past decade, which was the hottest decade in the historical record, Seventy-five countries set extreme hottest temperature records (33% of all countries.) For comparison, fifteen countries set extreme coldest temperature records over the past ten years (6% of all countries). Earth has now seen four consecutive months with its warmest temperature on record, and the first half of 2010 was the warmest such 6-month period in the planet’s history. It is not a surprise that many all-time extreme heat records are being shattered when the planet as a whole is so warm. Global warming “loads the dice” to favor extreme heat events unprecedented in recorded history.

VN:F [1.9.13_1145]
Rating: 0.0/10 (0 votes cast)
VN:F [1.9.13_1145]
Rating: 0 (from 0 votes)

Tags: , , , , ,

Permanent link to this article: http://www.euaclan.org/2010/08/over-15000-likely-dead-in-russian-heat-wave/

Apr
26
2010

An oceanic ‘fast-lane’ for climate change

Categories:

by

April 26, 2010

Αρκετά ενδιάφερουσα ανακάλυψη απο τους επιστήμονες σχετικά με την ύπαρξη ενός παγωμένου ρεύματος νερού στο νότιο ημισφαίριο μεταξύ Αυστραλίας και Ανταρκτικής.

Work in Japan and Australia has revealed that a deep-ocean current is carrying frigid water rapidly northward from Antarctica along the edge of a giant underwater plateau.

Other research teams had previously identified a deep current along the eastern edge of the Kerguelen Plateau, a more than 2,200-kilometre-long rise some 3,000 kilometres south-west of Australia. But estimates of its speed, taken as “snapshots” by instruments deployed from research vessels, had been “all over the place”, says Steve Rintoul, a physical oceanographer at the Antarctic Climate and Ecosystem Cooperative Research Centre in Hobart, Australia, and a co-author of the new study1.

Yasushi Fukamachi, an ocean scientist at Hokkaido University in Sapporo, Japan, led a team effort to determine the exact nature of the current. The researchers moored over 30 current and temperature recorders across its probable path and left these in place for two years. When they retrieved their instruments, the scientists discovered that the current, which flows at depths well below 3,000 metres, sometimes hit speeds greater than 700 metres per hour, carrying volumes as high as 30 million cubic metres per second. No other deep current in the Southern Hemisphere is known to move that quickly.

The current is formed by cold water sinking in the Ross Sea and off the coast of Adelie Land, on the Australian-facing side of Antarctica. Once in the abyss, the water flows eastward along the coast of Antarctica before hitting the Kerguelen Plateau. Then, just as the Gulf Stream hugs the eastern edge of North America, Coriolis force from Earth’s rotation causes the Antarctic water to embrace the plateau’s eastern flank. The result is a narrow, and so fast-moving, stream, about 50 kilometres wide.

This is significant because it represents a “fast lane” by which climatic and environmental changes affecting the Southern Ocean can propagate northward, says Alejandro Orsi, a physical oceanographer at Texas A & M University in College Station, who was not involved in the study. Proof that this is already occurring, he adds, can be seen from the fact that the deep waters near the Kerguelen Plateau already show “clear signs” of reduced salinity relating to changes in the rate of melting of Antarctic ice sheets.

Natural experiment

Understanding such currents could help scientists to predict how the world will react to increasing levels of carbon dioxide, says Richard Alley, a geoscientist at Pennsylvania State University in University Park. To begin with, he says, if heat goes into warming the deep ocean rather than surface waters, it will have less effect on sea-level rise because cold water in the ocean’s depths expands less than warm surface waters. Similarly, heat and carbon dioxide contained in deep-ocean currents are sequestered from the atmosphere until the water rises back the surface, many years later.

via NatureNews

VN:F [1.9.13_1145]
Rating: 0.0/10 (0 votes cast)
VN:F [1.9.13_1145]
Rating: 0 (from 0 votes)

Tags: , , ,

Permanent link to this article: http://www.euaclan.org/2010/04/an-oceanic-fast-lane-for-climate-change/

Page optimized by WP Minify WordPress Plugin