Calendaricities and Multimodality in the Eastern Mediterranean seasons

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Calendaricities and Multimodality in the Eastern
Mediterranean seasons

• Isabella Osetinsky, Pinhas Alpert
• Tel Aviv University

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Earlier works for Israel
Kutiel (1985) "trimodal rainfall course"- from
a number of stations for 1958/9 - 1977/8 Max I
10 Dec - 20 Dec Min I 30 Dec - 6 Jan Max II
20 Jan - 30 Jan Min II 19 Feb - 2 Mar Max
III 4 Mar - 29 Mar
Sharon Ronberg (1988) modes derived by 10-d
averages for 9 complete winters between 1964 and
1976 Max I 21 Nov - 20 Dec Min 21 Dec - 10
Jan Max II 11 Jan - 10 Feb Min 11 Feb - 10
Mar Max III 11 Mar - 31 Mar Min 1 Apr - 10
Apr Max IV 11 Apr - 30 Apr
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Term Singularity - up to 1963 Brier et al.
(1963, A Search for Rainfall Calendaricities ove
r the entire U.S.A. for 63 y, JAS ) Introduced
Calendaricity instead Brier (U.S. Weather
Bureau) was for calendaricities in his earlier
works, but in 1963 turned to against together
with his co-authors Shapiro Macdonald, (Air
Force Res. Lab, MA)
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in Duncan et al. (1965, The reality of
calendaricities in Indian rainfall for 10 y,
J.Atm.Terr.Phys.) were against referring
firstly to Laplace (1799, 1825) that warned of
the risk of presenting the effects of irregular
causes as laws of nature as has often happened
in meteorology
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Godfrey et al. (2002, Is the January Thaw a
Statistical Phantom?, BAMS ) In the absence
in the literature of even a plausible physical
explanation, the authors treated the synthetic
series and have failed to reject the null
hypothesis that mere sampling variations have
produced the warm excursion in northeastern U.S.
temperature records during late
January. against
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• Mapes, B.E., P. Liu, and N. Buenning, 2005
  Indian monsoon onset and Americas midsummer
  drought out-of-equilibrium responses to smooth
  seasonal forcing. J. Climate, 18, 1109-1115
  (published in these days, now available online in
  revised version). The authors use term of
  singularities
• AGCM ECHAM4 simulations for
• Mapes, B.E., N. Buenning, I.-S. Kang, G. N.
  Kiladis, D. M. Schultz, and K. M. Weickmann,
  2005 Strides, steps and stumbles in the march of
  the seasons BAMS, in revision. The authors recall
  the use of calendaricities as well as
  singularities.
• Used Global reanalyses, gridded rain gauge
  data, satellite products, and climate model
  outputs. Wavelet analysis.
• Seasonal phenomena shown here include
• The annual harmonic of near-surface temperature,
  which already poses a challenge for climate
  system models
• Semiannual variations of jet streams and the
  Northern Hemisphere mid-winter minimum of storms
  
• Summer rainy-season onsets in the monsoons
• Mid-summer enhancements of the oceanic
  subtropical highs and associated monsoon rainfall
  breaks
• Sudden onset of autumn rains in the northwest
  U.S.
• A climatological oscillation in late northern
  winter associated with the long-debated January
  thaw' in North America.

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From Alpert et al. (2004), A new seasons
definition for the EM
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?????? ??? ??? ??????? ???? 28 ??? ?? ??? 1948
1975 ?- 1976 2003 (NCEP/NCAR reanalysis) ??
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http//www.grida.no/climate/ipcc_tar/wg1/057.htm
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1976-2003
1948-1975
http//www.cgd.ucar.edu/cas/jhurrell/nao.stat.wint
er.html
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1948-1975
Total Winter Lows
????
1976-2003
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Present study 1948-2003 Max I 18-19 Dec Min I
30 Dec Max II 19 Jan Min II 25 Jan Max
III 6 Feb Min III 21-22 Feb Max IV 1
Mar Min IV 13-14 Mar Max V 20 Mar Min V
12 Apr Max VI 19 Apr
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Present study 1948-1975/1976-2003 Max I 19/18
Dec (1 Jan) Min I 30/25 Dec(10 Jan) Max
II -/18 Jan Min II -/26 Jan Max III 1/8-9
Feb Min III 19/24 Feb Max IV 3-4 Mar/28
Feb Min IV 12-13/14 Mar Max V 19/20
Mar Min V 10/15 Apr Max VI 18/22 Apr
Rainfall extremes derived from the study by
Sharon (1990), 1940-60/1960-80 Max I 27/11
Dec Min I 2 Jan Max II 14/17 Jan Min
II 26/31 Jan Max III 1/7 Feb Min III
17/19 Feb Max IV 28 Feb/3 Mar Min IV 11
Mar Max V 1 Apr/23 Mar Min V 11/1 Apr Max
VI 19 Apr
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Max III
Max II
Max IV
Max IV
Max I
Max VI
max
max
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Major Maxima
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Late September and early November maxima
Cyprus Lows
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max
Max IV-VI
Consistence in timing for shallow Cyprus Lows
rather than for deep CL and for transitional
periods rather than for high winter
Max I-V
Max VI
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late Oct floods
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early Nov floods
drier late Dec early Jan
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For two non-overlapping periods 1948-1975 and
1976-2003, both Winter Lows and RST frequencies
have the peaks on certainly dates, but,
surprisingly, rather for their non-typical
seasons than for typical.
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For two non-overlapping periods 1948-1975 and
1976-2003, the weak and medium Persian Troughs
distributions are similar the medium Persian
Trough prevails over the weak for the first half
of summer, while for the second they are nearly
equal.
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For two non-overlapping periods 1948-1975 and
1976-2003, both Sharav Lows, to the west and over
Israel, have close distribution for the
spring, with totals nearly the same in amplitudes
and timing. Both also appear separately, in
autumn, with a minor peak in October.
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