As they say, data is/are where you find it/them. Was flying back from Beijing yesterday (by date, day before by day) and the plane had a GPS/sensor display. It showed the plane's position on the globe. It showed the speed. Also, from time to time, it showed altitude and temperature. I noticed this on the flight out, so on the flight back, was prepared to take the values down.
FWIW, Here are altitude/temperature data for the Beijing takeoff, and the Newark descent:
TAKEOFF FROM BEIJING Alt (m) TempC ==============
41 26
462 23
1172 21
1217 19
1228 19
1892 17
2322 15
3009 12
3544 8
4794 3
8534 -27
10058 -38
DESCENT TO NEWARK Alt(m) TempC ====================
10363 -36
8229 -24
6553 -12
6400 -11
6248 -10
5943 -7
5469 -5
5213 -4
4930 -3
4865 -2
4849 -2
4771 -1
4665 -1
4500 0
4223 2
3994 3
3841 4
3671 5
3654 5
3505 6
3349 7
3260 8
3106 9
2950 9
2725 10
2567 11
2442 12
2291 13
2146 14
2135 14
1954 15
1836 16
1828 15
1775 16
1566 17
1522 17
1492 17
1361 19
1229 19
1214 19
1192 19
1096 20
974 20
908 20
858 20
747 21
639 22
541 22
449 23
337 24
201 24
113 24
21 24
The relationship is remarkably linear, just as it is in the NOAA Standard atmosphere. A least squares fit intercept should yield the ground temperature as the intercept and the slope should be about the same in both places.
This linear relationship is used to predict pressure and density at various altitudes. It isn't foolproof, though. In spring, for example, the slope is mush steeper.
NOTES: Descents are slower than takeoffs, so there are more descent data..
The display showed data in metric, and sometimes in English with metric XLation. There were more metric values so I used them.
Regards,
-Larry Curcio