<p>The stratopause is separating the stratosphere from the mesosphere around 47-53 km (29-33 mi) altitude. Standard atmosphere models give its temperature as minus 2.5°C, but how strong are its variations as per latitude and season? What's the lowest and what's the highest stratopause temperature ever recorded by radiosonde or sounding rocket data, and at what time and above what latitude?</p>

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2022-07-28T07:40:54.980Z
You're asking for radiosonde or sounding rocket data.  Radiosondes do not reach the stratopause and sounding rockets are rare.  Satellites, however, routinely measure upper stratospheric temperatures.  Would you consider those for an answer?
gerrit
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2022-07-28T10:06:06.367Z
@gerrit If they really do, of course. But how do you measure temperature from a distance? Can air be shown in infrared? Some balloons such as BU-60-1 do reach the stratopause btw. Data from reentering Space Shuttles would be appreciated as well.
Why On Earth
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2022-07-28T11:03:16.610Z
Yes, temperature can be measured from a distance using atmospheric sounding, either infrared or microwave, with instruments such as IASI and AMSU.  I'm not sure if IASI profiles extend to the upper stratosphere, but AMSU does.  The resolution (both vertical and horizontal) is much worse than for in-situ measurements, but the temperature distribution in the upper stratosphere is quite smooth, so it's not a big problem.  There is also remote sensing of upper stratospheric temperatures with ground-based microwave radiometers.
gerrit
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2022-07-28T11:12:28.417Z
@gerrit So in-situ measurements would be best, but if there are only data from the ground or from orbit available, one may answer based on that.
Why On Earth
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2022-07-28T22:44:02.090Z
Anecdotal datapoint: This week, decending over London through the stratospheric minimum, the board instruments were showing -36 deg C... global averages are not representative of local temperatures.
AtmosphericPrisonEscape
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2022-07-29T05:18:54.440Z
@AtmosphericPrisonEscape How did you ascend into the upper stratosphere? And at what altitude exactly did you see the value? At 50 km (31 mi)? And why is it a stratospheric minimum currently; I thought that in summer the stratosphere and -pause would actually be warmed up and therefore _above_ the ISA average.
Why On Earth
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2022-07-29T08:08:10.430Z
@WhyOnEarth: Airplane, I was a passenger, altitude was 11.05 km. I cannot tell you why they stratosphere is colder there. It's just one datapoint, not a global view. You can probably have a look at weather apps like windy, and check the 0.1 bar level for its temperature distribution.
AtmosphericPrisonEscape
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2022-07-29T08:21:26.103Z
@AtmosphericPrisonEscape I see. My question was on the stratopause (stratosphere-mesosphere boundary) 50 km up. You were slightly above the ISA's tropopause in the lower stratosphere (in fact you were probably still in the troposphere because it's summer so the warmed-up troposphere is stretched). Btw, how did you get the value of 11.05 km? Normally, airliners would fly e.g. at FL360 (10.98 km) or FL370 (11.3 km), not inbetween round flight levels. Were you still ascending/descending already?
Why On Earth
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2022-07-29T08:30:49.443Z
@WhyOnEarth: Descending from a high-altitude flight, we also had significant tailwind for most of the way, maybe that helped keep a high altitude, dunno.
AtmosphericPrisonEscape
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2022-07-29T09:05:47.193Z
@AtmosphericPrisonEscape Interesting. Do you recall your maximum cruise altitude and the temperature up there? It should be even colder.
Why On Earth
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2022-07-29T11:38:24.363Z
@Whyonearth No, I only started paying attention to the instrumental data ~20 mins before landing, on a 10 hour flight.
AtmosphericPrisonEscape
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2022-07-29T15:05:29.420Z
@AtmosphericPrisonEscape I hope you could find some sleep. Such flights are terrible.
Why On Earth
<temperature><stratosphere><radiosounding>
What are the coldest and hottest ever recorded temperatures at the stratopause?
Why On Earth
# What are the coldest and hottest ever recorded temperatures at the stratopause?

(Asked by: username_0 on 2022-07-27)

The stratopause is separating the stratosphere from the mesosphere around 47-53 km (29-33 mi) altitude. Standard atmosphere models give its temperature as minus 2.5°C, but how strong are its variations as per latitude and season? What's the lowest and what's the highest stratopause temperature ever recorded by radiosonde or sounding rocket data, and at what time and above what latitude?

**Tags:** temperature, stratosphere, radiosounding

> **Comments:**
> **username_1**: You're asking for radiosonde or sounding rocket data.  Radiosondes do not reach the stratopause and sounding rockets are rare.  Satellites, however, routinely measure upper stratospheric temperatures.  Would you consider those for an answer?  
> **username_0**: @username_1 If they really do, of course. But how do you measure temperature from a distance? Can air be shown in infrared? Some balloons such as BU-60-1 do reach the stratopause btw. Data from reentering Space Shuttles would be appreciated as well.  
> **username_1**: Yes, temperature can be measured from a distance using atmospheric sounding, either infrared or microwave, with instruments such as IASI and AMSU.  I'm not sure if IASI profiles extend to the upper stratosphere, but AMSU does.  The resolution (both vertical and horizontal) is much worse than for in-situ measurements, but the temperature distribution in the upper stratosphere is quite smooth, so it's not a big problem.  There is also remote sensing of upper stratospheric temperatures with ground-based microwave radiometers.  
> **username_0**: @username_1 So in-situ measurements would be best, but if there are only data from the ground or from orbit available, one may answer based on that.  
> **username_2**: Anecdotal datapoint: This week, decending over London through the stratospheric minimum, the board instruments were showing -36 deg C... global averages are not representative of local temperatures.  
> **username_0**: @username_2 How did you ascend into the upper stratosphere? And at what altitude exactly did you see the value? At 50 km (31 mi)? And why is it a stratospheric minimum currently; I thought that in summer the stratosphere and -pause would actually be warmed up and therefore _above_ the ISA average.  
> **username_2**: @username_0: Airplane, I was a passenger, altitude was 11.05 km. I cannot tell you why they stratosphere is colder there. It's just one datapoint, not a global view. You can probably have a look at weather apps like windy, and check the 0.1 bar level for its temperature distribution.  
> **username_0**: @username_2 I see. My question was on the stratopause (stratosphere-mesosphere boundary) 50 km up. You were slightly above the ISA's tropopause in the lower stratosphere (in fact you were probably still in the troposphere because it's summer so the warmed-up troposphere is stretched). Btw, how did you get the value of 11.05 km? Normally, airliners would fly e.g. at FL360 (10.98 km) or FL370 (11.3 km), not inbetween round flight levels. Were you still ascending/descending already?  
> **username_2**: @username_0: Descending from a high-altitude flight, we also had significant tailwind for most of the way, maybe that helped keep a high altitude, dunno.  
> **username_0**: @username_2 Interesting. Do you recall your maximum cruise altitude and the temperature up there? It should be even colder.  
> **username_2**: @Whyonearth No, I only started paying attention to the instrumental data ~20 mins before landing, on a 10 hour flight.  
> **username_0**: @username_2 I hope you could find some sleep. Such flights are terrible.  

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## 0 answers

