Australian Daily Reset Issues

Archive Archived Weather Display Problems
1

As noted in a number of previous treads, WD does not correctly handle daily and monthly reset systems used by the Australian Bureau of Meteorology for both live data and when converting corrected log files. Some key reset time challenges that WD needs to handle include:

  • Rainfall: total from previous 24 hours to 9AM - recorded on the day of measurement
  • Maximum Temperature : maximum value over previous 24 hours to 9AM - recorded on previous day
  • Minimum Temperature : minimum value over previous 24 period to 9AM - recorded on the day of measurement
  • Maximum Wind Gust: maximum value over previous 24 period to 12 midnight - recorded on the day covering the previous 24 hours
    More information on reset times and data recording is provided at the following website: http://www.bom.gov.au/climate/cdo/about/about-stats.shtml

I have spent quite a lot of time trying to identify where and why various issues are occurring and how to use the existing WD functions to try and manually fix data problems as they happen. The following quick summary on rainfall issues may help others with similar problems in the short term and hopefully give Windy with some ideas on possible fixes to WD in the long term.

If anyone has come up with better solutions for fixing rainfall or any other data for the Australian reset times can you please provide.

As a start, when trying to enter or correct monthly data in WD using the Australian requirements you essentially need weather records from 9 am on the last day of the previous month to 8:59 am on the first day of the following month (at present WD logfiles generated using the Australian Reset Time only go from 9 am on the first day of the month).

Issue 1 - Monthly Rainfall Totals
The first issue is that WD incorrectly adds rainfall from 9 am on the last day of the month to 12 midnight to the previous monthly total (i.e. rainfall does not reset @ 9 am) For example for February:

28 2 2011 8 59 29 85 26.2 1015 0 2 145 0 85.7 944.2 1375.2 35.8 28 2 2011 9 0 29 85 26.2 1015 1 3 149 0 [color=red] 0 944.2[/color] 1375.2 35.9

Instead of 9 am, the monthly rainfall resets @ 12 midnight:

28 2 2011 23 59 23.6 89 21.7 1013 1 2 179 0 2.3 946.5 1377.5 23 1 3 2011 0 0 23.6 89 21.7 1013 0 2 177 0 [color=red] 2.3 0[/color] 1377.5 23

The new month then starts by missing the rainfall that fell from 9 am to midnight:

1 3 2011 8 59 25.5 89 23.6 1015 0 0 230 0 [color=red]3.3 1[/color] 1378.5 26.9 1 3 2011 9 0 25.5 89 23.6 1015 0 0 230 0 0 1 1378.5 26.9
If you want to correct log and data files you will need to modify the log file using excel and then convert to data file.

In WD the monthly total is relatively easy to adjust using two options:

Rain to date screen - month manual entry
Control panel > offsets & initial rain

Windy, hoping that you can fix the issue with the monthly rainfall relatively easily to at least remove one step in this process.

To fix the daily rainfall records see the second issue.

Issue 2 - First Day of Month Rainfall

The second issue is that WD shows the incorrect rainfall for the first day of each month. In the monthly log files the rainfall for the first day is actually located at the end of the previous month. At the moment WD will substitute a 0 or random value until the end of the month when it will use the rainfall from the first day of the following month.

This can be seen in the following monthly summary tables:

Rain to date > Detailed Rain Chart
View > Averages/Extremes

So far I have identified a solution that can only fix one of these tables but not both at the same time. You need to decide which is more important. Follow these steps:

View > Averages/Extremes
correct/check data button
load the data or log file > select the month you are trying to correct > load the data file to correct the daily rainfall data button

It is important at this point to note that the raintall shown for Day 1 will actually be the value for Day 2 and so on until the last day of the month which will show the incorrect value for the real Day 1.

Enter the correct rainfall for the real first day of the month into the last day (i.e. for February this would be Day 28) and then:

may sure the last date is showing in the Date of Correction
Use the corrected amount button
Use the Save Changes button

If you look up the monthly summary tables you will see:

  • Rain to date > Detailed Rain Chart (rainfall totals for the month you are trying to fix are now correct)
  • View > Averages/Extremes (daily rainfall totals for month you are trying to fix will remain incorrect)

The alternative solution is to repeat the above but enter the correct daily total for the preceding month into that actual month you are trying to fix. Then following the remaining steps.

If you then look up the monthly summary tables you will see:

  • Rain to date > Detailed Rain Chart (rainfall totals for the month will show an incorrect value -now preceding month)
  • View > Averages/Extremes (daily rainfall totals for the preceding month will now be correct)
  • View > Averages/Extremes (daily rainfall totals for month you are trying to fix will remain incorrect)

Windy, if you can get WD to fix both monthly summary tables in the one step that would also be a great improvement.

I am more than happy to trial any potential fixes for the rainfall or other data collection.

2

I added option for Australia 9am reset
where the monthly rain fall is reset at midnight on the last day of the month, instead of 9am on the 1st day of the month (as it is in NZ)
I have tested and this works (occurs at 12:01am)
that rain total is correctly put into the values for View, Rain chart, at that time (I have tested and checked this)
but the logfile is not reset until 9am, so it will then show that monthly rain reset occuring in the logfile

are you saying that this midnight rain reset should not be occuring and instead it should be occuring at 9am on the 1st?
there are people that tell me one thing and people that tell me another

I do not know what to believe

Maximum Wind Gust: maximum value over previous 24 period to 12 midnight - recorded on the day covering the previous 24 hours

I did not know that Australia uses midnight reset for the Maximum wind gust

3

Windy

are you saying that this midnight rain reset should not be occuring and instead it should be occuring at 9am on the 1st?

Neither, the monthly rainfall reset to 0 mm should be started at 9 am on the last day of each month. All rainfall after this time belongs to the first day of the following month.

I did not know that Australia uses midnight reset for the Maximum wind gust

Neither did I until recently. Along with the rainfall issue and recording the max and min temperatures to 9 am on different days it makes things quite complicated.

Cheers

4

Windy

April logfile indicates that latest version of WD (Build 42) still resets Australian monthy rainfall total @ midnight rather than @ 9 am on the last day of the month (see below). No rainfall on the last day to see if there would also be issues with the daily totals on the first and last days of the month.

30 4 2011 8 58 24.7 70 18.9 1015.0 3 5 197 0.0 0.0 573.0 2984.2 25.7 30 4 2011 8 59 24.8 71 19.2 1015.0 2 4 177 0.0 0.0 573.0 2984.2 25.8 30 4 2011 9 0 24.9 71 19.3 1015.0 2 4 166 0.0 0.0 573.0 2984.2 25.9 30 4 2011 9 1 25.0 71 19.4 1015.0 3 4 158 0.0 0.0 573.0 2984.2 26.0

30 4 2011 23 58 20.1 82 16.9 1014.0 2 3 277 0.0 0.0 573.0 2984.2 20.7
30 4 2011 23 59 20.1 82 16.9 1014.0 2 3 277 0.0 0.0 573.0 2984.2 20.7
1 5 2011 0 0 20.1 82 16.9 1014.0 3 4 280 0.0 0.0 0.0 2984.2 20.7
1 5 2011 0 1 20.1 82 16.9 1014.0 3 3 284 0.0 0.0 0.0 2984.2 20.7

Cheers

5

Hi FNQ,
I have also pointed out this problem in a thread a few says ago.
I would describe the problem a little differently.
On the last day of the month the monthly total is reset at midnight rather than at 9AM on the morning of the first day of the new month.
Then the daily total is reset again at 9AM as it should be.
This means (as far as I can see) that any rain between midnight on the last day of the month and 9AM on the first day of the month is “lost”
I was unaware of any differences of reset time for other values. I think this should be checked and, if true, maybe should be ignored due to the complexity.
It would be great if this persistent problem could be sorted out.
I am happy to help if I can.
w0mbat

6

Unfortunately FNQ is correct about the max wind gust recording period, though why it should be different to other values is a mystery to me. Below a quote from BOM definitions:-

Maximum wind gust (km/h)
Maximum wind gust recorded for each calendar month and the year, over the period of record. A gust is any sudden increase of wind speed of short duration; typically a 3 second time period is used. The maximum wind gust for a day is measured from midnight to midnight. If, for some reason, an observation is unable to be made, the next observation is recorded as an accumulation. Accumulated data can affect the Date of the Maximum Wind Gust, since the exact date of occurrence is unknown.

Frankly, I just don’t understand this. Surely the rain month goes from 9AM on the 1st of the month to 9AM on the 1st of the next month. I have not been able to find a BOM definition of a recording month but surely the first and last day of a month must fit the same definition of a recording day as any other day. Otherwise it just doesn’t make sense to me.
w0mbat

7

Wombat & Windy

Frankly, I just don't understand this. Surely the rain month goes from 9AM on the 1st of the month to 9AM on the 1st of the next month. I have not been able to find a BOM definition of a recording month but surely the first and last day of a month must fit the same definition of a recording day as any other day. Otherwise it just doesn't make sense to me

The Australian BOM records rainfall @ 9 am on the date it was read. In NZ they assign the 9 am rainfall to the previous day.

As far as the BOM is concerned any rainfall measured from 9 am on the last day of the month to 9 am on the first day of the next month is actually assigned as the rainfall for the 1st day of the month. So the reality in Australia is that monthly rainfall is recorded from 9 am on the last day of each month to 9 am on the last day of the following month.

Although it can be confusing and difficult to program for, I doubt the BOM will change this anytime soon given 120 years of records and the continued widespread manual recording of rainfall data in smaller communities (including the two wettest towns in Australia).

Cheers

8
April logfile indicates that latest version of WD (Build 42) still resets Australian monthy rainfall total @ midnight rather than @ 9 am on the last day of the month (see below).

its all very confusing

I thought that is what you wanted

but I see now you do not want that

instead the 9am reset time stays in place
except that the monthly rain total is reset at 9am on the last day of the month
yes?

as for the maximum windspeed, I could add an option for that

9

actually you can set the hour to reset the daily maximum gust individually, in the units setup, times setup
so you can set that to 0 for midnight if you want to

as for the 9am aus rain reset, the latest version update now changes to reset the monthly rain total to 0 at 9am on the last day of the month

(and the daily total stays at normal (i.e 9am)
I assume the year total then also gets reset to 0 at 9am on the last day of the month as well?

10

Hi Windy,
I also am pretty confused by this. It is not fair for you to spend time changing the programming if the definitions are not certain.
I have just contacted BOM to try and get clear and unquestionable definitions of recording periods and reset times. I will post again as soon as I get an answer.
w0mbat

11

I think its clear enough that the monthly rain total has to be reset to 0 at 9am on the last day of the month
instead of on the 1st day of the month, as it is in NZ

the other quirk that is with the Aus 9am reset is that the day of the rain is on the day of the 9am reset, not the day prior, as it is in NZ

why do you aussies have to be so different eh?

12

Windy

I assume the year total then also gets reset to 0 at 9am on the last day of the month as well?

That is correct.

Thanks for the effort in making the changes.

actually you can set the hour to reset the daily maximum gust individually, in the units setup, times setup so you can set that to 0 for midnight if you want to

Using that at the moment without any problems that I know of.

Cheers