Mammals and fungi

I have no images of the mammals but the sightings have been:

• A Grey-headed Flying-fox dining in a flowering banksia in a neighbour's garden; and 
• An Australian Fur Seal lounging on the suface about 200m off Point Difficult yesterday afternoon.

A friend from a weather forum reckons the wet weather at Katoomba is causing the bioluminescent fungi in that area to be performing well.  I haven't managed to locate any of that in this area yet but there are getting to be a range of fungi about.  The identifications blow are rather tentative - comments welcome.

Leucocoprinus birnbaumii (Angophora Drive)

No ID yet (Point Difficult)

 Macrolepiota clelandii (Mirrabooka Avene, near top entrance to Angophora Drive)

Musings about water levels and rain

In the Community Facebook page a comment has been made that the day after the opening was made the level of the Inlet has risen by 50 mm.

That led me to wonder how that relates to recent rainfall.  In what follows many of the necessary bits of data are not available but I think it sort of hangs together.

My weather station (Angophora Drive) has recorded somewhat over 50mm in the last 7 days.  One could make an assumption that this is about average for the catchment of the Inlet  - and checking against BoM data for Cann River and Cathcart that seems not unreasonable.  There are 3 things that could happen to the rain:

1. Sink into the ground
2. Run off into the the river system; 
3. Evaporate.

Given recent weather I think evaporation is not a major player.  I have no idea of the split between points 1 and 2: on the one hand the soil currently has plenty of capacity (favouring (1)) but on the other hand a significant fall in a short time will favour (2).  For a mind-game, I assume 10% of the rain has run off.

It is going to take a while for the water to get here.  The headwaters of the Genoa are at least 45 kms from the mouth of the Inlet in a straight line and probably double that in river kilometres.  That means it is going to take a while  - probably 3-4 days (??) - for some of the run off water to get here.  As most of the rain was several days ago one could assume that most of it has now got here, probably arriving in the last two days

I have read somewhere today that the surface area of the Inlet is  25 sq km (or 2,500 Ha).  Eyeballing Google Earth and following the course of the Genoa and Wallagaraugh Rivers suggests that the catchment area of the Inlet is about 40 km x 25 km (~80,000 Ha).  For the sake of argument, say I have got that way wrong and it is only 40,000 Ha.  That still means the area of the catchment is 16 times that of the Inlet.  

Bringing these guesses together we have 50mm of rain x 10% run-off x 16 times area (50*0.1*16)= an "expected" rise of 80 mm.

Then bring in the new factor of the opening to the sea.  which is about 10m wide.  I have run out of imagination in trying to assess how much water is flowing out in any given time period, but if it has released close to half the water that has arrived through the Narrows in the last 24 hours I reckon that is both believable and beneficial.

The Inlet now has an outlet.

I recently got an email from a resident of Manila, Philippines to the effect that the Inlet was to be opened on 21 March.  This was going to happen so that it finished at low tide (1330).  We drove down on that day and had finished unpacking the car by 1530, so I took myself off.

So did quite a few other people!

On the way I noted the height of the water relative to the road ...

,,, the fish cleaning station and....

.... the wharf.

I had wondered how they would get earth moving equipment into the area.  The answer is to heap sand over the rocks at Bastion Point!

Excavator tracks - and notice the number of people on the beach.

Gippsland Ports had declared a no=go area near the outlet and sent a boat to monitor it.  I think this tinny driver got the word.

Some images of the channel.

There is obviously a good flow!

There was a lot of sand moved!  I think the Ranger calculated 2000 cubic metres in total (and I'm not sure is that included the ramp at Bastion Point).

The local kids turned up in force!

This was being monitored by a Ranger to ensure nothing dangerous happened.  He explained the role of the various agencies involved:

• The Gippsland Catchment Management Authority look at the theoretical aspects of the opening and decide when it could be done.  This seems a fair summary of the considerations.
• They get Parks Victoria to look after the operation (ie do the work); 
• Gippsland Ports are responsible for the maritime safety (ie keeping boats out of a dangerous area)

Basically all sensible when explained that way.

The next day (22 March) there is a good flow to the oceean

 .. and the water has started to carve its own way into the exit.

The opening is in a good spot as the area the waders are using is still accessible with dry feet.  This is a pair of Red-necked Stints.

Walking back along the beach a couple of very large dark gulls appeared,  (The nearest one is actually smaller and white - or Silver.)

They are Immature Pacific Gulls: note the massive bill.

The beach was well endowed with Bluebottles so shoes are good!

Sunrise and an Egret

After yesterday's continual murk, it was good to see the cloud breaking up at sunrise.

Mid afternoon I was pretty excited to see this bird shown in the following image land in the next-door-but-one paddock. Initially identified as a Cattle Egret,

... but this swiftly revised as this image to Alpaca Egret!

Birding and other stuff

The day started off well with 3 Wedge-tailed Eagles in a cypressy-looking tree near home.  The third ne is a young bird, indicated by a yellow arrow.  It whinged constantly.

A birding friend from Canberra was in town today so we spent the morning visiting a few sites.  The first, Gun-Club Track, was a waste of time: the only bird seen was a Welcome Swalllow.  We did hear a Treecreeper nearby but still pathetic.

We then stopped at Betka Beach where the birds were more obliging, especiallythe Hooded Plovers of which we saw 2.  Hopefully Jnr was nearby somewhere.

On to Bastion Point where we got some good birds despite some funsters walking right through the flock of Gulls and Terns.  Bird of the Day was Red-necked Stint  but there were also good numbers of Red-capped Plover and a large flock of Short-tailed Shearwaters over the ocean.

On to the recycled Water Treatment Plant.  A first sighting there was a Koala in the gum plantation..

The walk in was quite quiet in terms of birds but the ponds soon began to deliver,  Overall numbers were quite good, but not record breaking.  A young Wedgetail - possibly the one seen near home this morning as its only 2.5kms away - posed nicely

As we moved to the big pond my friend spotted what he first thought was a discarded tyre.  Then he realised it was a humungous Red-bellied Black Snake.  We estimated it as at least 2m long and the body as thick as our arm.

It was happily  eating frogs and such like but on dropping a couple of rocks it poked its head up.

Calling in at the small wetland with a hide we saw 2 Spotless Crakes ...

,, and a single Black-fronted Dotterell.

Getting back to the caravan Park and another Koala had been spotted.

You can see Autumn from here!

The start of March was very warm, but it has cooled off a lot.

The trend for maximum gets disrupted by the warm Sunday 10^th, but the downward trend for minimum is very clear.

One way of assessing the relative warmth is by looking at the average temperature month to date for the current period and comparing that with the historic average.  (It is possible to approximate average temperature by the average of daily maximum and minimums.)  The difference between the current and historic averages is referred to as the anomaly.  This next chart shows the anomaly - currently 2.2^oC - as it has evolved though the month so far.

My conclusion is that if Autumn is not actually here yet we can certainly see it not too far away.

Interestingly the value of the anomaly is the same as has been calculated by another recorder for Bateman's Bay.

Long term rain and temperatures

The objective of this post is to report on a couple of interesting findings about longer term aspects of the weather in Mallacoota.  In summary:

• there has been a decreasing amount of rainfall for the last 5 years and the trend may not yet have turned.; and
• there is little change in the average daily maximum and minimum temperatures across the month of March. 

Long Term Rain

When looking at the weather for Carwoola I found that taking a long term view demonstrated the depth of the current drought rather well.  So I decided to take the same approach for Mallacoota, using BoM data.

My starting point was a 12 month rolling total which blocks any seasonal patterns.

I couldn't pick a significant trend in the overall series but did note the downwards slide towards the end!  The mean 12 months rainfall is 936 mm and the median is 917 mm.  It is a bit hard to  work out the value of the mode but looking at a bar chart of major size classes ...

... suggests that it would fall at around 900mm.  That grouping of averages suggests that the values are not too far off a normal distribution

I then extended the rolling periods to 18 months and 24 months, giving the following chart.

In each case there is a rather consistent downwards look to the last 5 years, so I charted that separately.  The values of R² confirm a significant downward slope.

While the 24 month series ends with an uptick it is probably too soon to say the drought is broken.

Long term average March Temperature extremes

To support some thoughts about temperatures for this month I calculated the average monthly maxima and minima by day using BoM data since 1994.

I was impressed by how flat the graph was, as I was expecting a pronounced downwards trend though the month.  With an R² of 0.39 I don't think the value for maximum is significant and even that for minima ( 0.60) is anything to get excited over.

Seasons in Mallacoota (pt 1)

A key analytic issue is that seasons are best indicated by the regular seasonal changes in the environment.  I don't at present have the data needed to assess this in detail so have labelled the post Part 1.  However my inclination at present is to stick to the 4 official BoM seasons beginning on the 1^st of September, December, March and June.

The best background to my views on this are contained in a post I created for our place in Carwoola.  To summarise the outcome of that for Carwoola my set of seasons there were:

• Spring: September, October
• Summer: November, December, January, February
• Autumn; March, April, May and June
• Winter: July, August

This hints at one of the issues in moving from an astronomic (equinox, solstice) based definition of  the seasons.  That is that seasons vary according to place, with major variables being (IMHO)  elevation, distance from the coast and latitude.  Where an analysis is trying to be all things to all places in (eg) Australia it is probably as well to pick a standard based on astronomy - which obviously does have an impact - as anything else.

Note that I say " a standard based on astronomy" not "the standard based on astronomy" since Australia uses the beginning of months while the actual astronomical events are around the 21st of March, June, September and December. 

A key factor in my variation from the standard was that it didn't seem to fit well to my observations of natural phenomena in Carwoola (nor particularly well to gross changes in the weather over a year).

For Mallacoota, at this stage, I only have a limited number of items to consider.  I do have a series of weather observation data from BoM going back to 1974 (rainfall) or 1993 (temperatures).  I also have a series of observations of birds covering a rather vague period, but heavily biased towards the period from 2014 onwards.

Weather series

Temperature

I have looked at two series about temperatures,  The first shows the monthly average maxima and minima.

 I can see little in the way of abrupt changes in these series, such as would indicate a seasonal break. January and February are clearly the warmest months and July and August are clearly the coldest.  It isn't clear to me that a case exists for preferring December over March as part of Summer, nor preferring June over September as part of Winter.

My second chart looks at the number of days each month with a maximum over 25^oC or a minimum below 5^oC.  (Those numbers were largely chosen by eyeballing the data, but using a limit of 5^oC does give a clearer picture than using 10^oC.)

Concentrating on the 4 "marginal" months December has more warm days than March (and the same  - 0 - cold days).  June is lower than September for warm days and well above it for cold nights.

Rainfall

I looked at the average daily rainfall, and the number of days with >0.2mm of rain, by month.  Neither series showed anything I could pick as a seasonal break.  So I won't waste your downloads with more graphs!

Birds

The main indicative interest of birds as auguries of weather - and I don't want anyone to think that I have been disemboweling them - is the movement of migratory species.  

From a broad scrutiny of the eBird data available to me it seems that most species migrate in the period February to April.  Trying to establish whether which of those months is the month of change is somewhat more difficult in Mallacoota than it was in Carwoola.

• I began by looking at known migrant species and seeing when the number of records dropped.  There were very few species for which April seemed key.  13 species seemed to have headed out in February against 11 in March.
• The most spectacular movements I have seen are Red Wattlebirds and Yellow-faced Honeyeaters flying West up the Inlet - presumably to cross at The Narrows.  This can amount to hundreds of Wattlebirds and thousands of Honeyeaters per day and occurs in late March - April.  However there are many reports of both species right through the year..
• I then examined the number of species with a higher number of reports in February than March (114 spp) and March vs April (143 spp).

Again I don't consider this to be conclusive.  

Weather report February 2019

In a past life I composed a monthly weather report for the Carwoola community.  This was based on recordings from my Davis Vantage Vue weather station.  I intend to do the same at Mallacoota, having fired up the Davis on 13 February.

For this month, as I only have 50% of the month covered by my station, much of what follows will be data I have downloaded from the BoM site.  I have included some comparative data for my site as some form of quality assurance.

The process of setting up my station and an initial comparison with BoM is included in this post.  In case folk are wondering, I have not got a 'net enabled Station: the original extra cost was a dissuasion as was the dodginess of my internet connection in Carwoola!

Summary

As far as I can tell, on limited data, it was a fairly normal February.  Rainfall was on average, maxima were a tad high  and minima were a little low.  

Rainfall

My first chart compares this year with last year and the average x month back to 1985.  BoM have some data going back to 1974, but some years have several months missing.  A 30 year series is probably long enough to give a broad picture!

 We are about on average for February after a rather dry January.

The next chart shows the annual totals from 2018 back to 1985.  Although 2018 was below average, at 757mm it is not far out of line compared with data in the period 1993 to 2010.

 Looking at falls to the end of February and expanding that pro-rata to estimate the annual total (a dodgy process at this stage of the year) we end with an estimate of  close to 800mm for this year.

Temperatures

Maximum temperatures

Again looking at this month compared with last year and the average (from 1994 onwards) the month was a little cooler than 2017, but average daily maximum was a little higher than the average.

 The next chart compares my Davis with the BoM site.  Obviously very close agreement in both values and pattern (correlation coefficient 0.96) .

Minimum Temperatures

January had high minima but for February they were well below both 2018 and 2016.

The comparison of my Davis with the BoM site is interesting in that the pattern is very similar (correlation coefficient (again) 0.96) but the actual values are fairly closely based around 1^oC higher at home than for the BoM site on the coast.  I attribute this to the Davis being sheltered from a cooling sea breeze overnight.

Wind

The BoM doesn't seem to do much about publishing data on wind and it is a cramp downloading it a month at a time.  I might explore a little more and try to get some back data for later,  In the meantime here is the comparison of my data with the BoM stuff I have got.

As might be expected from a site right on the coast with the anemometer on a 10m pole the BoM gets more wind than we do at home in a site sheltered  from the south and a 1.8m pole!

I think my site is good enough to say if a month is windy or not windy, but probably not too good  for intensive analysis.

I have now downloaded 13 months of BoM data and have a graph of average daily gust by month.

With such a limited set of data its dangerous to make big calls but there doesn't look to be any obvious seasonal pattern there and the variability (ie relative standard deviation) is quite low at ~6%

Humidity

Again it is time consuming to download the BoM data.  I'll try to build up a series before the end of March.  Been there, done that, for the 2 standard series about humidity at 9M and 3PM (1500 hrs) over the last 13 months.

June 2018 was a very wet month, seeming to have rained just about every day.  The values for other months are in a quite tight band and Relative Standard Deviation is pretty low at ~8%, even including the June value.

Here are the series for February 2018.  There is much less difference between the two readings than used to be the case in Carwoola

Comparing those series with mine, I am surprised that my site is more humid early in the day.  Possibly this is some effect of the overnight sea breeze?  The afternoon readings are very similar  in level and pattern.