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2020 officially saw a record number of $1 billion weather and climate disasters.
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Something that must be considered when comparing historical records is the effect of differences in radiation shields compared to conventional Stevenson Screens. Smaller multi-layer shields can show differences of several degrees in times of high solar radiation and light winds. I know I'll get attacked for stating the above so let me show the data.
Compare Wednesday's max temperatures of the agrimet stations (small shield, first map) to those of the standard synoptic stations (Stevenson Screens, second map). The synoptic network is less dense but all stations are several degrees below the agrimet ones.
This study investigated the difference between a the two types of shield and found a large spike (2 - 2.5 degrees) in the smaller shield (Type A below) during early afternoon, when solar radiation was at its peak.
Between 1300 and 1500, when global solar radiation averaged 935 W m2 and wind speed 2 m/s, both the standard deviation and the range of temperature in the Stevenson screen were smaller than comparable values for the two commercial screens: 0.39 and 1.72 °C, respectively, compared with 0.51 and 2.42 °C for screen ‘type B’, and 0.65 and 3.16 °C for screen ‘type A’. The time lag is illustrated in Figure 10: following sunrise, temperature in the lightweight commercial screen increases more rapidly than in the Stevenson screen, resulting in a temperature difference of up to 2 °C.
For most of the day, temperatures from the Stevenson screen remain about 1.5 °C lower. As solar flux decreases in the afternoon, the lightweight screen cools more rapidly, and the temperature difference is eroded.
Statistical analysis may not always reveal the full extent of differences between the Stevenson screen and modern gill-type screens. Table II shows typical statistical values for temperatures recorded in the Stevenson screen, in the two commercial screens and in a mechanically aspirated double-barrelled shield used as a reference on a sunny day. with light but fairly constant winds of about 1–2 m/s. As in the previous experiment, there is no ‘absolute’ reference temperature. However, it was considered that an air speed of about 6m/s over both surfaces of the interior shell of the mechanically aspirated shield was sufficient to ensure that the temperature of this shell would be very close to that of the air, resulting in negligible radiant heat transfer from the environment.
Differences between the temperatures recorded in the different screens appear to be quite small – maximum, minimum and mean daily temperatures were about 0.3–0.5 °C higher in the naturally ventilated screens than in the mechanically aspirated one. Yet, as Figure 10 shows, the temperature error in screen ‘type A’ (defined as the difference relative to the aspirated, double-walled screen) was in fact not negligible for most of the day: it was greater than 1 °C for most of the sunshine hour, and exceeded 2 °C for part of the time.
With the proliferation of these newer automated weather stations and their use in setting records, it would stand to reason that an increasing trend in records being broken may result. Now Akrasia will no doubt fob this off as me "furiously backpeddalling", but for most of the year and in most places, these difference may not amount to much. But in extreme cases, that is where these differences will be highlighted.
But again, I'm sure the WMO know this and consider it in their records...
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I'm not sure records, past or present, prove anything either way though. We had a 10 day heatwave here in this country recently and no max temp records were broken, but the sheer duration of the heatwave was historically noteworthy.
Edit:
Compared to RTE
New heat record in Italy as anticyclone 'Lucifer' sweeps in
State funded media showing no bias at all there. 🤑 - Nabber.
Southern Italy was under a slack trough, not a luciferin Anticyclone when that temp was reached:
Media, eh?
New Moon
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your answer indicates to me that you’re just playing lip service to a claim that you do not deny climate change is happening. Do you accept that the earth has warmed by about 1.1c relative to pre-industrial averages?
If not, how much do you think it has warmed and what peer reviewed data can you point to to support this?
You also fundamentally miss the point of AGW
AGW doesn’t mean that the AMO or the Synoptics, or land use changes etc, do not affect the weather. All of the natural variability and other human factors still drive the weather. The human ghg emissions don’t account for all of the heat in a heatwave. There could have been a heatwave in British Colombia without AGW, it could even have been a record breaking one, but the CO2 signal added heat to that heatwave and also affected things like how long it persisted and where it occurred.
you talk about the AMO as being a driver of weather, climate change has absolutely overwhelmed the AMO ‘signal’
SSTs are so much warmer now that to see an AMO trend at all, you need to subtract the AGW related element from the observations to see where we would be in the AMO cycle without AGW
https://www.nature.com/articles/ncomms1186/figures/1
AGW now dwarfs the AMO, so if you believe the AMO is a significant driver of weather events and extremes, then surely AGW is an even bigger driver than the AMO was?
no climate scientist thinks the C02 signal is the only factor in the weather, all the Synoptics still matter, but those Synoptics are affected by the enormous amounts of energy added to the planet because we have inadvertently geo-engineered our atmosphere
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I seriously question some of the data that are included in making that 1.1 degrees figure, for reasons such as outlined in my post from the other day. You have still not commented on that, good or bad, but if increasing numbers of different types of stations are increasingly being included in land temperature records then it stands to reason that this figure will be falsely inflated.
You said (re. the Canadian heatwave)
the CO2 signal added heat to that heatwave and also affected things like how long it persisted and where it occurred.
Exactly how much extra heat did 140 ppm of extra CO2 add, given that we don't really know what ECS is? What's the formula for calculating it?
Regarding SST, let's take a look at the chart in the recently published State of Ireland's Climate 2020, in which they showed data for Malin Head up to 2018 (not sure why not include 2019 and 2020). In any case, given my extensive skills at inserting datapoints on charts 😉, I've added the 2020 data in orange (11.25, from here, not yet quality controlled). I can't find 2019 data anywhere, but from the second graph on that met.ie page it looks slightly higher than 2020, with 2021 so far coming in below 2020).
Your charts only goes up to 2008. The Met Éireann report chose to quote the anomaly for period from 2009, with no word on the most recent trend, which would appear to be flat. The AMO increased during the mid-1990s and the SST followed. The AMO has remained flat positive since, as has the SST. Only one station, but I didn't choose it. They also didn't show data for the previous positive AMO phase pre-1960, which is a pity, as it would probably have shown a positive SST anomaly too. That wouldn't suit the narrative, though. I think it's pretty clear that the AMO is the dominant factor in our SST, which in turn will have an effect on temperature and rainfall.
But let's talk about sea level, which they also reference in the report. They strangely show no timeseries for that but say that
"Satellite observations indicate that the sea level around Ireland has risen by approximately 2-3mm/year since the early 1990s"
and that
"Analysis of sea level data from Dublin Bay suggests a rise of approximately 1.7mm/year since 1938 which is consistent with global average rates."
There is no mention of the shorter-term trends within this data series, which show high variability, especially since 2016 in Dublin. Further afield, Malin Head doesn't have an up-to-date dataset available here (unless someone knows of another source), but there's not much of a longterm upward trend up to 2002 anyway.
Nearby Portrush has a better series. It shows a trend of ~0.9 mm/yr from 1995-2020, which is significantly less than the 2-3 mm quoted. I know different places have different rates, but the data would suggest it's a lot more complicated than is being expressed in that climate report.
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Just to whinge a bit more about local station effects. This is the actual Siracusa station that reported 48.8 C last week.
The temperature sensor shield is highlighted. It's sitting a few cm directly above a horizontal metal pole, which itself is attached to a vertical pole containing the large datalogger unit.
In most cases the effects of these nearby artificial surfaces would be negligible, However, when you get to talking about those extreme cases, these effects must become significant. The horizontal metal pole is likely to be a significant source of heat, especially as it's right below the sensor. Similarly the nearby datalogger, which is a box of electronics which itself will heat up inside, however the outer housing, despite being white, will still be a source of heat. I can't touch my balcony railings, coated with white PVC, in Sardinia during the middle of the day. There is also a dark green railing immediately surrounding the sensors.
Zooming out a little, this is the immediate local site. A small road and thick concrete wall are just a few metres away. Again, I know from experience how hot those types of walls get during the afternoon.
Even the ground gets extremely hot in this setup at this time of the year. The Google Map image above is from July 2019 and shows fairly bare and scorched ground. There is still come green in that image, but it is more likely to be completely devoid of any green grass at this time of the year, as is currently the case in Sardinia. My nearest station there was reporting maximum surface temperatures (T-Superficiale) of up to 48 C last week while air temperatures (T-aria) were up to 40 C. We would not see such high surface temperatures if covered in green grass.
The other stations in the Siracusa region, while still high, didn't reach the same highs. The hottest, Lentini, was around 2 degrees lower (46.9 C) It's still almost 40 km away from the Siracusa station, but is only 5 km from Catania Sigonella airport to its north and a similar distance inland. It reached a max of "only" 44.4 C on the same day. That's a significant difference of 2.5 degrees.
The point of all this is that extreme temperatures are the focus of much of the talk about climate change, however little consideration is given to the points above.
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