Winter is coming

Last night Daylight Saving Time switched back to its winter position. That itself is nothing special. Well, maybe it is because the EU is really thinking of abandoning the twice per year hour shift, it is biologically deregulating.

But that is not why I write this [short] message. The switch itself showed up nicely on the temperature graph of my weather station and, as if it was saying Winter is Coming, exactly on the time of the hour switch, the temperature fell from 15 to 10 degrees within an hour and a half.

It shows all nicely on the chart (after the break). Continue reading

Behaviour of pwsFWI with first rain

One of the goals of the current implementation of pwsFWI is to see its behaviour under all conditions. It is therefore very interesting to see that behaviour in the two stations in semi-arid zones (in Australia and in Spain) where long dry periods may suddenly alternate with rain after which the drought returns. Continue reading

Sites which carry the Fire Weather Index pwsFWI

This blog message contains a list of sites, which carry the pwsFWI Fire Weather Index. Please look here for more information, or look here for it’s distribution location on the Cumulus support forum. Look here for its scientific background. Check out the map as well for stations carrying CumulusUtils. 

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On the programming of CumulusUtils

Introduction

Having developed theoretically a Fire Weather Index (see my pwsFWI) and creating a first implementation of it in C for analytical purposes, I needed to take the software a bit further to make it more robust and useful. I had some feedback which made me realize it was urgent to have a good Fire Weather Index (FWI) for Personal Weather Stations (PWSs).

This blog is about the context and the actual programming requirements.

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Evaluating FWI for Personal Weather Station

In An effort for a Simpler Fire Weather Index I described my new FWI and the theory behind it. In short, this pwsFWI (as I have baptised it) is meant to be a generic FWI, valid everywhere and independent of geology and vegetation.

The pwsFWI is a (not too) complex measure of local meteorology, an indicator composed of humidity, wind speed and temperature. It fluctuates under ‘normal’ conditions and if it becomes dryer (a longer period without rain, the number becomes higher. As soon as it starts raining, the value starts dropping.

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An effort for a simpler fire weather index

In this blog I will propose a fire weather index for PWSs. The goal is to get fuel parameters out of the equation. This means that species, litter type or geography, will not play a role as they do in the Canadian FWI. As such, it connects with a recent new development described by Goodrick et.al. 2 .

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The Canadian FWI

Introduction

I will describe the Canadian FWI as it appears in (scientific) literature. The basic reason for describing this complex fire-weather index is, that it is heavily used in some big countries, notably Canada, France, Australia and New Zealand and that the description of the method of calculation is not readily available.

The FWI also has been introduced in 2007 [1] as the method to assess the fire danger level in a harmonized way throughout Europe.  

Some extensive studies have been made, to measure its performance and its relevance. FWI also contains most parameters relevant to estimating the danger level of the weather in relation to nature fires. In short: the FWI is an important tool for estimating and studying fire weather and fire spreading, with a huge knowledge base spanning almost 100 years. Continue reading

Another top10 approach

An example for this top10 approach you will find on the weather site.

As a variation to existing top10 lists, I wrote a small program (in C) which reads dayfile.txt from Cumulus once per day just after midnight and for selected measurements it creates a sorted top10-list. From that list it creates a HTML-table and writes that to a text-file. That file can be included by the user on a website wherever he wants simply by a PHP-include (which is the easy way to include I think).

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