Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Archives for February 2015

Donald and David’s Relevance to Climate Science

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“CRICKET legend Sir Donald Bradman is a useful metaphor for the escalating global row over claims the world’s leading climate agencies have been messing with the weather.

David Stockwell has made a submission to the Panel.
David Stockwell has made a submission to the Panel.

Imagine, for instance, if some bureau of sport were to revise the Don’s batting average in test cricket down from 99.94 to 75 after adjusting for anomalies and deleting innings of 200 runs or more.

What if the bureau then claimed another batsman had exceeded the Don’s revamped record of 75 to become the greatest ever?”

So begins a long article in today’s The Weekend Australian on page 20.

Journalist Graham Lloyd was in fact building on an analogy in a submission to the new panel, by David Stockwell; the Panel ostensibly established to review the Bureau of Meteorology’s homogenization of Australia’s official temperature record.

In his submission David Stockwell, an adjunct research fellow at Central Queensland University explains:

“Every portrayal of historical data should be historically accurate, else it becomes revisionism, and strays out of the domain of science and into the domain of ideology and politics. While step-wise adjustments are intended to compensate for real changes in the baseline temperature that result from, often undocumented, changes in instrumentation or relocation of stations, the cumulative effect of back-propagating step adjustments is to corrupt the official record.”

Neither Christine Milne nor Tony Jones are likely to follow up on this.  So, we need you to get your letter into The Editor and/or make comment under the article…

http://www.theaustralian.com.au/news/features/upping-the-heat-on-climate-number-crunchers/story-e6frg6z6-1227242096753

And also contact your local MP and/or news outlet and explain why they need to report this.

Reality…

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Accepting the reality of change gives rise to equanimity – Allan Lokos.

Yeppoon coastline in November 2011, looking south east to what was once a volcanic plug…
Yeppoon coastline in November 2011, looking south east to what was once a volcanic plug…

Missing Observational Data for Middle Percy Island

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IT is valid for the Australian Bureau of Meteorology to estimate the intensity of a cyclone using computer models when it is far out to sea.  But once that same cyclone passes over a weather recording station the modelling data must be updated with real world observational data.

In the case of Marcia even after this cyclone passed over Middle Percy Island recording a  minimum central pressure of only 972 hPa, maximum wind gust of 208 km/h and maximum wind speed of 156 km/h, the Bureau continued to report only on the basis of output from a computer model.  The cyclone was clearly a category 3 system, yet the Bureau called it as a 5.

The Bureau has since removed the observational data that was once available on their website, I printed it off at the time and had it digitized this morning.  That information is here:

Middle Percy Obs Now Removed

It would be travesty if Marcia was recorded as a category 5 cyclone at landfall based on output from a dysfunctional computer model, rather than as a category 3 as clearly indicated by the observational data.

How do we know that Cyclone Marcia was a Category 5 at landfall?

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Track map BOMTHE Australian Bureau of Meteorology issued a media release last night (19thFebruary) with the headline “Tropical Cyclone Marcia to reach Category 5 system at landfall”.    This morning there was extensive media reporting of Marcia having reached landfall as a Category 5.

But where is the evidence?  And who is asking for it?  Like the Bureau, the Australian media seem intent on hyping the event, rather than providing any critical or dispassionate assessment.

The first technical bulletin for Marcia, issued at 4pm today states that, “surface observations have not captured the highest winds,” and acknowledges that the minimum pressure so far recorded has been 975 hPa inside the eye wall at 1.30 pm at Rockhampton.

In fact, this central pressure only qualifies Marcia as a Category 2.  As one would expect of a category 2, both Rockhampton and Yeppoon have sustained relatively minor house damage and significant damage to trees.

Just before the cyclone made landfall it passed over Middle Percy Island, to the north of Rockhampton, and the lowest central pressure recorded for the system then was 971.6 hPa at 3.39 am this morning.   A wind gust of 208 km/hr was recorded at 4.30 am, which suggests Marcia was almost a Category 3 at this time, even though its central pressure was never recorded as below 970 hPa.   The central pressure of a cyclone needs to be somewhere in the 970 to 955 hPa range to be a Category 3.

This would suggest that even as Marcia approached the Queensland coastline it was never more than a Category 2.

Indeed the raw observational data available at the Bureau’s website would suggest that Cyclone Marcia made landfall just south of Middle Percy Island as a Category 2 approaching a Category 3, but had already weakened to a very ordinary Category 2 approaching Category 1 by the time it reached the city of Rockhampton.

This evidence, however, contradicts the track map at the Bureau’s website, and also the extensive media suggesting that Cyclone Marcia made landfall as a Category 5, and was still a Category 3 system when it reached Rockhampton.

The Australian Bureau of Meteorology has been hyping the possibility of a devastating cyclone hitting the Queensland coastline all year.  It forecast that Marcia would hit as a Category 5 cyclone, but where is the evidence?

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Thanks to everyone who has emailed me today with best wishes, assuming I was in Yeppoon when Marcia hit.   Our house there is still standing, with some trees down in the front yard.  I was in Brisbane last night, and am now in Noosa.