Category Archives: 21st-century climate

May Climate Anomalies Log

Posted in 21st-century climate, Calendar month anomalies, Climate Change, Manilla NSW by

Heat Indicators log for May months

This post is the third in a set for the 12 calendar months. Graphs are sixteen-year logs of the monthly mean anomaly values of nine climate variables for Manilla, NSW, with fitted trend lines. I have explained the method in notes at the foot of the page.

Raw anomaly values for May

Extreme values of May anomalies in this period were:
Daily Minimum Temperature anomaly -3.6 deg: May 2006;
Morning Dew Point Anomaly +3.6 deg: May 1999;
Morning Dew Point Anomaly -3.9 deg: May 2006;
Morning Dew Point Anomaly -3.2 deg: May 2011;
Morning Dew Point Anomaly -4.4 deg: May 2012;
Temperature range anomaly (minus) -3.2 deg: May 2006.

Trend lines for May

Heat Indicators

The trends of all three air temperature anomalies were almost the same, except that anomalies of daily minimum temperature were more negative. All began high in 1999, reached a minimum in 2002, a maximum in 2007, and a minimum in 2011-12. The trend of subsoil temperature was contrary, and generally increasing.

Moisture Indicators log for May months Continue reading →

17 Years of “Droughts and Flooding Rains” at Manilla

Posted in 21st-century climate, Anomalies smoothed, Australian Climate, Climate Change, Manilla NSW by

Manilla 17-year smoothed rainfall anomaly record

Times when Dorothea Mackellar’s “droughts and flooding rains”* affected Manilla in the years from 1997 are shown by the wavy line on this graph. The climate swings in and out of times of high and low rainfall.

Peaks or troughs were often a year or two apart, but most of them were not very far from the normal rainfall value. Only two of the troughs were so far below normal that they were severe droughts: August 2002, and December 2013 (or maybe later). Milder droughts came in October 2006 and September 2009.
The rainfall in these 17 years was not below the long-term average, but slightly above it. As well as droughts there were two peaks of extremely high rainfall: in July 1998 (when the new Split-Rock reservoir suddenly filled) and in November 2011. These “deluges” had rainfall that was further from normal than the low rainfall in the droughts. Other rainfall peaks came in November 2005, October 2008, and October 2010.
In total, there were nine peaks and troughs with rainfall outside the normal range. Six of them came in the spring months of September, October or November.
Peaks and troughs in rainfall at Manilla quite often come near times of La Niña and El Niño. These are events in the record of Pacific Ocean temperatures called ENSO (El Niño – Southern Oscillation). The ENSO record for the last 17 years is shown in the second graph.

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April Climate Anomalies Log

Posted in 21st-century climate, Calendar month anomalies, Climate Change, Manilla NSW by

Heat Indicators log for April months

This post is the second in a set for the 12 calendar months. Graphs are sixteen-year logs of the monthly mean anomaly values of nine climate variables for Manilla, NSW, with fitted trend lines. I have explained the method in notes at the foot of the page.

Raw anomaly values for April

April anomalies had few extreme values in this period:
Daily Maximum Temperature anomaly +3.4°: April 2005;
Morning Dew Point Anomaly -3.3°: April 2008;
Morning Dew Point Anomaly -4.8°: April 2013;
Rainfall anomaly +79 mm: April 2003.

Trend lines for April

Heat Indicators

The trends of all three air temperature anomalies were almost the same. They began very low in 1999, reached a maximum in 2002-3 and a minimum in 2009-10. The trend of subsoil temperature began similarly, but with much less variation, and peaked in 2012.

Moisture Indicators log for April months

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March Climate Anomalies Log

Posted in 21st-century climate, Calendar month anomalies, Climate Change, Manilla NSW by

Heat Indicators log for March months

This post is the first in a set for the 12 calendar months. Graphs are sixteen-year logs of the monthly mean anomaly values of nine climate variables for Manilla, NSW, with fitted trend lines. I have explained the method in notes at the foot of the page.

Raw anomaly values for March

Extreme values for March anomalies in this period were:
Daily Minimum Temperature anomaly -2.9°: March 2008;
Morning Dew Point Anomaly +3.5°: March 2000;
Morning Dew Point Anomaly -3.2°: March 2008;
Rainfall anomaly +61 mm: March 2007;
Percent cloudy mornings anomaly +37%: March 2011.

Trend lines for March

Heat Indicators

Daily maximum temperature showed minima about -1 deg in 2001 and 2014, and a maximum about zero in 2007.
Daily minimum showed a minimum two years later, about 2003, then rose in parallel with daily maximum, but ended very high.
Subsoil temperature did not agree, and varied less. It had maxima in 2002 and 2012. It may show a lag of five years behind daily maximum.

Moisture Indicators log for March months

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Profile of an Extreme Drought

Posted in 21st-century climate, Climate events, Manilla NSW by

Rainfall vs Maximum temperature, 2002 droughtAt Manilla, NSW, there was a drought in 2002 that was extreme, but brief. There have been no other extreme droughts at Manilla in the 21st century. The current drought is not as bad (yet).
The first graph shows a profile of the 2002 drought. Low rainfall is at the top, and hot days are on the right. Droughts, with low rainfall and hot days, will be near the top right corner. Normal climate is marked by a rectangle (coloured aqua (aqua)) in the middle.
The climate in these months moved into drought and out of it. January 2001 (Start) had perfectly normal climate with no drought, and so did February 2003 (Finish). Rainfall first became lower than normal after January 2002, and reached a minimum 27 mm below normal in July 2002. Rainfall returned to the normal range by December 2002. Day-time temperature went above the normal range in May 2002, reached a peak 1.3 degrees above normal in September-October 2002, and fell back into the normal range in January 2003. For rainfall lower than normal, the drought lasted ten months: for days hotter than normal, it lasted eight months. In this drought, the time of lowest rainfall came two to three months earlier than the time of hottest days.

(There is more detailed analysis of  the 2002 drought in a post dated September 2004.)

Graphs showing the progress of the drought as rainfall shortages are in the post “The 2002 rainfall shortages at Manilla”.

The loop on the graph shows this drought as a simple event with a beginning, a middle, and an end. Droughts are not usually seen to be so simple. This graph is made using two “tricks”: anomalies and smoothing. You must judge whether you trust them to describe the drought as it happened.

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