Monthly Archives: November 2013

Sydney’s changing sea level

More data from the BOM, this time I’m plotting their historical tidal measurements along with moving averages over 6 months, 1 year, 5 years, 10 years and 30 years.

Tidal measurements are for Sydney taken from the Fort Denison gauge, the data includes monthly averages for low and high tides and the mean, going back to 1914.

Like the temperature data there are local rises and falls that last 10 years or more, but the consistent long term trend is up.

Click through to have a play with the chart, select the data sets you want and they will be displayed.

sydney sea level
Click through to see Sydney’s changing sea level


Ant Fight! ( Sugar ant v. Black ants )

Camponotus consobrinus (sugar) and Ochetellus glaber (black)

I was taking the 2 boys for a walk down to the river on the weekend when we came across a lone sugar ant in the middle of a swarm of about 20 tiny black ants on a patch of exposed sandstone. At first it looked like the small black ants were teaming up to attack the sugar ant, but after watching them for a while it was clear the sugar and was not trying to get away, and was in fact chasing and attacking the much smaller black ants!

The black ants were fast, but the sugar ant was nimble, twisting and turning to catch the black ants in it’s large mandibles. Sometimes a black ant would latch into the sugar ants leg but it didn’t seem to cause the sugar ant much trouble, it would be kicked or nipped of in pretty short order. Eventually all the black ants were gone, all fled, and the sugar ant was left patrolling the rock. It was a good match up.

Sugar ants are common in the area, they’re found around the garden and in the bush. They are largish, around 20mm, but apparently they do not have a sting like some other ants, their bite can be felt but it’s not painful.

Sugar and fighting off a gang of black ants.
A Sugar ant pounces on a much smaller black ant



Sydney’s Changing Climate

Besides the boring old weather the Bureau of Meteorology website has a lot of pretty cool stuff. Something I’ve been digging into lately is their climate data. Depending on the weather station you can find rainfall, maximum and minimum temperatures going back over 150 years.

I’ve used their temperature data for the Observatory Hill station in Sydney to make a graph over time, I’ve also calculated moving averages over various time periods. It’s turned out some pretty interesting results. There’s a clear warming trend since the early 1900’s for maximum temps and around the mid 1940’s for minimums, but it’s not all smooth, there have been some ups and downs that have lasted over 10 years.

Click through to the interactive graph and have a play, you can turn the various data series on and off to compare. You have to be a bit patient, it can take a few seconds after you click to send through the new data points and graph them.

The change in maximum Sydney temperatures over time
The change in maximum Sydney temperatures over time