3-year trends to August 2008

Parametric plots of smoothed climate variables at Manilla
“Years with unusual trends”

Trends to August 2008

These graphs, ending with raw data for August 2008, show fully-smoothed data from September 2005 to February 2008. They include all months of the calendar years 2006 and 2007.
Smoothed daily maximum temperature anomaly (X-axis on all graphs) began 2006 high in the “normal” range, fell to normal by June, and rose again to +0.63°  in November and December. It then fell from high to very low through 2007, reaching the record low value of -1.61°  by February 2008. (Note added: This record low maximum temperature anomaly stood for only 19 months, until September 2010.)
Smoothed rainfall anomaly peaked at +20.6 mm in November 2005, fell rapidly to -11.7 mm in June 2006 and slowly to -14.6 mm in October 2006. It rose again to just above normal by February 2007, and changed little in the following year.
Smoothed percent cloudy mornings followed a similar course to that of rainfall but, as temperature fell through 2007, cloudiness (unlike rainfall) increased, as is normal,  along the blue trend-line.
(Note added in May 2014: Although the minimum value of the cloudiness anomaly in August 2006 (-7.7%) is less negative than the record minimum in August 2002 (-11.3%) (or even than the minimum in February 2005 (-9.1%)) it is more negative than any later value. No smoothed negative values at all were recorded in almost seven years between February 2007 and October 2013.)
Smoothed dew point anomaly also followed a similar course to that of rainfall but, unlike cloudiness, actually declined as temperature fell during 2007. Temperature range anomaly moved like dew point anomaly.
Daily minimum temperature mainly varied in the same sense as daily maximum temperature, but at a higher rate. As an exception, from January to June 2007, it rose slightly as maximum temperature fell. That moved the curve towards a more “maritime” climate for the rest of the time. Subsoil temperature anomaly moved in a similar pattern.

Unusual trends

Through the years 2006 and 2007 shown here, the climate moved as much along the axis from top left to bottom right, as along the usual axis from top right to bottom left. It departed from the typical Quasi-biennial oscillation of “droughts and flooding rains”*. (Note added: The extreme negative maximum temperature anomaly of February 2008 was the only one on this record that was not linked to an extreme positive rainfall anomaly.)
(Note added concerning global temperature: At this time there was a sudden major cooling in mean air temperature, both locally and globally. This linked post  shows that, when 37-month averages of global and local values are plotted, mean temperature fell from a peak in April or May 2006 to a trough in October 2007, breaking the global warming trend. The global (GISS) value fell by 0.074° (and the Manilla value by 0.48°). The connection is enigmatic. The unusual trends shown here do not match the dates of the cooling event, but come mainly before or after it.)

* By arrangement with the Licensor, The Dorothea Mackellar Estate, c/- Curtis Brown (Aust) Pty Ltd.

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Normal values are based on averages for the decade from March 1999. They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

(Note added in May 2014: A much later post titled “3-year trends to May 2010” is the first of a consecutive series of parametric plots, updated monthly at the time of observation and originally posted elsewhere.
This earlier data was not edited in this form at the time.
To display all existing fully-smoothed data points at least once, I have prepared these back-dated posts in the same format for:
“3-year trends to August 2002” which includes smoothed data September 1999 to February 2002, covering the calendar years 2000 and 2001.
“3-year trends to August 2004” which includes smoothed data September 2001 to February 2004, covering the calendar years 2002 and 2003.
“3-year trends to August 2006” which includes smoothed data September 2003 to February 2006, covering the calendar years 2004 and 2005.
“3-year trends to August 2008” (this post) which includes smoothed data September 2005 to February 2008, covering the calendar years 2006 and 2007.
In these back-dated posts the anomaly values depend on climate normals that are based on the decade ending February 2009, and were thus not available until after that date. I have written the posts as if they were available at the time.
In places I have written some “Notes added in May 2014” (like this) commenting on how values observed at that time relate to more recent events.)



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