DIURNAL VARIATION IN AIR TEMPERATURES AT MSL ON MARS
This page under construction on 8/4/2016
This article was begun on August 1, 2016, just five days shy of the 4th (terrestrial) anniversary of the landing of MSL on Mars. It is also well past two Martian years since landing. While most people who look at Mars weather statistics see only the numbers presented by NASA that we offer here, we have so thoroughly audited what they have issued that frankly we are beginning to feel as though we have lived at Gale Crater, Mars ever since the landing there on August 6, 2012. As such, we have often noted that while night air temperatures are fairly steady there is much more variation in day temperatures. To get a measure of this variation we focus here only on sols where the low air temperature was -74° C. As Figure 1 and Table 1 show on such days the air corresponding highs varied from +3° C down to as low as -27° C, a range of 30 ° C (54° C). If, as NASA contends, there were a near vacuum atmosphere, we would expect far less variation. Table 1 shows the same data as was presented on Figure 1 but it adds the calculation results for the length of daylight hours for each solar longitude (Ls) where a minimum air temperature of -74° C was recorded between landing of the Mars Science Laboratory on August 6, 2012 (Sol 1) and Sol 1,417 on August 1, 2016. The full calculations for day length at all solar longitudes are provided on this site at Table 5 of Martian Sunrise and Sunset Calculations.
TABLE 1 Summary of MSL length of daylight hours and high air temperatures for MSL sols in which the low air temperature was -74° C. | |||||
B | C | D | E | F | |
DATA LINE WITH -74°C LOW | SEASON | LS | MSL SOL NUMBER | ~HOURS AND MINUTES OF DAYLIGHT | HIGH TEMP °C |
1 | WINTER YEAR 1 | 157 | 13 | 11 hr 55.04 min | -15 |
2 | WINTER YEAR 1 | 157 | 14 | 11 hr 55.04 min | -16 |
3 | WINTER YEAR 1 | 161 | 21 | 11 hr 56.12 min | -3 |
4 | WINTER YEAR 1 | 162 | 22 | 11 hr 56.40 min | -6 |
5 | WINTER YEAR 1 | 166 | 30 | 11 hr 57.50 min | -3 |
6 | WINTER YEAR 1 | 167 | 31 | 11 hr 57.77 min | -23 |
7 | WINTER YEAR 1 | 173 | 43 | 11 hr 59.44 min | -12 |
8 | WINTER YEAR 1 | 175 | 45 | 11 hr 59.99 min | -9 |
9 | WINTER YEAR 1 | 175 | 46 | 12 hr 0 min | -12 |
10 | WINTER YEAR 1 | 177 | 49 | 12 hr 0.56 min | -10 |
11 | WINTER YEAR 1 | 179 | 52 | 12 hr 1.12 min | -7 |
12 | SPRING YEAR 1 | 180 | 55 | 12 hr 1.41 min | -2 |
13 | SPRING YEAR 1 | 182 | 58 | 12 hr 1.96 min | 0 |
14 | SPRING YEAR 1 | 186 | 64 | 12 hr 3.09 min | 0 |
15 | SPRING YEAR 1 | 202 | 91 | 12 hr 7.53 min | -1 |
16 | SPRING YEAR 1 | 202 | 92 | 12 hr 7.54 min | -1 |
17 | SPRING YEAR 1 | 229 | 134 | 12 hr 14.31 min | -1 |
18 | SUMMER YEAR 1 | 339 | 311 | 12 hr 7.25 min | -8 |
19 | SUMMER YEAR 1 | 341 | 315 | 12 hr 6.71 min | -10 |
20 | SUMMER YEAR 1 | 341 | 316 | 12 hr 6.4 min | -16 |
21 | SUMMER YEAR 1 | 342 | 318 | 12 hr 6.43 min | -4 |
22 | SUMMER YEAR 1 | 344 | 320 | 12 hr 5.88 min | -4 |
23 | SUMMER YEAR 1 | 345 | 322 | 12 hr 5.60 min | -5 |
24 | SUMMER YEAR 1 | 345 | 323 | 12 hr 5.48 min | -6 |
25 | SUMMER YEAR 1 | 347 | 327 | 12 hr 5.05min | -8 |
26 | SUMMER YEAR 1 | 348 | 329 | 12 hr 4.77 min | -7 |
27 | SUMMER YEAR 1 | 349 | 331 | 12 hr 4.49 min | -3 |
28 | SUMMER YEAR 1 | 351 | 334 | 12 hr 3.93 min | -6 |
29 | SUMMER YEAR 1 | 358 | 348 | 12 hr 1.96 min | -8 |
30 | WINTER YEAR 2 | 165 | 697 | 11 hr 57.21 min | -4 |
31 | WINTER YEAR 2 | 178 | 720 | 12 hr 0.84 min | -1 |
32 | WINTER YEAR 2 | 179 | 722 | 12 hr 1.12 min | 1 |
33 | SPRING YEAR 2 | 181 | 724 | 12 hr 1.68 min | 1 |
34 | SPRING YEAR 2 | 183 | 728 | 12 hr 2.24 min | 1 |
35 | SPRING YEAR 2 | 186 | 733 | 12 hr 3.09 min | -2 |
36 | SPRING YEAR 2 | 188 | 737 | 12 hr 3.65 min | 3 |
37 | SPRING YEAR 2 | 193 | 745 | 12 hr 5.05 min | 3 |
38 | SPRING YEAR 2 | 199 | 755 | 12 hr 6.71 min | 2 |
39 | SPRING YEAR 2 | 215 | 781 | 12 hr 10.96 min | 3 |
40 | SPRING YEAR 2 | 218 | 785 | 12 hr 11.72 min | -5 |
41 | SPRING YEAR 2 | 218 | 786 | 12 hr 11.6 min | -4 |
42 | SPRING YEAR 2 | 238 | 816 | 12 hr 16.14 min | -7 |
43 | SUMMER YEAR 2 | 274 | 871 | 12 hr 19.28 min | -7 |
44 | SUMMER YEAR 2 | 281 | 883 | 12 hr 18.94 min | -6 |
45 | SUMMER YEAR 2 | 304 | 919 | 12 hr 15.96 min | -3 |
46 | SUMMER YEAR 2 | 307 | 924 | 12 hr 15.16 min | -1 |
47 | SUMMER YEAR 2 | 317 | 941 | 12 hr 12.96 min | 0 |
48 | SUMMER YEAR 2 | 317 | 942 | 12 hr 12.8 min | -1 |
49 | SUMMER YEAR 2 | 327 | 958 | 12 hr 10.45 min | -9 |
50 | SUMMER YEAR 2 | 332 | 967 | 12 hr 11.72 min | -2 |
51 | SUMMER YEAR 2 | 340 | 982 | 12 hr 9.14 min | -4 |
52 | SUMMER YEAR 2 | 341 | 984 | 12 hr 6.71 min | -6 |
53 | SUMMER YEAR 2 | 342 | 986 | 12 hr 6.43 min | -1 |
54 | SUMMER YEAR 2 | 343 | 987 | 12 hr 6.15 min | -7 |
55 | SUMMER YEAR 2 | 344 | 989 | 12 hr 5.88 min | -10 |
56 | SUMMER YEAR 2 | 347 | 995 | 12 hr 5.05min | -4 |
57 | SUMMER YEAR 2 | 348 | 997 | 12 hr 4.77 min | -13 |
58 | SUMMER YEAR 2 | 350 | 1000 | 12 hr 4.20 min | -12 |
59 | SUMMER YEAR 2 | 351 | 1003 | 12 hr 3.93 min | -10 |
60 | SUMMER YEAR 2 | 352 | 1004 | 12 hr 3.65 min | -9 |
61 | SUMMER YEAR 2 | 355 | 1010 | 12 hr 2.84 min | -11 |
62 | AUTUMN YEAR 2 | 3 | 1025 | 12 hr 0.56 min | -14 |
63 | AUTUMN YEAR 2 | 7 | 1032 | 11 hr 59.44 min | -16 |
64 | AUTUMN YEAR 2 | 74 | 1177 | 11 hr 44.58 min | -27 |
65 | AUTUMN YEAR 2 | 74 | 1178 | 11 hr 44.52 min | -23 |
66 | WINTER YEAR 3 | 146 | 1329 | 11 hr 52.18 min | -15 |
67 | SPRING YEAR 3 | 185 | 1401 | 11 hr 44.58 min | -4 |
68 | SPRING YEAR 3 | 190 | 1409 | 12 hr 2.81 min | -9 |
As can be seen above, the shortest day with low of -74°C had a high of -15°C. This was on Sol 1,329 at Ls 146 in the winter of MSL Year 3. The length of daylight then was about 11 hours 52.18 minutes (the lowest amount of daylight at Gale Crater is about 11 hours 43.76 minutes for Ls 90 when winter begins).
The longest day with low of -74°C had a high of -7°C. This was on Sol 871 at Ls 274 in the early summer of MSL Year 2. The length of daylight then was about 12 hr 19.28 minutes (the largest amount of daylight at Gale Crater is just just a few seconds longer at about 12 hours 19.34 minutes for Ls 270 when summer begins). There were several winter sols in the first 1,417 Martian days of MSL operations where the REMS Team and JPL reported warmer highs than the -7°C seen in the summer for Sol 871. Specifically, they are summarized on Table 2 below:
TABLE 2 Summary of MSL length of winter daylight hours and high air temperatures for MSL sols in which the low air temperature was -74°C and in which the high air temperature was equal to or warmer than the -7°C seen in the summer on MSL Sol 871 at Ls 274.
| |||||
B | C | D | E | F | |
DATA LINE WITH -74°C LOW | SEASON | LS | MSL SOL NUMBER | ~HOURS AND MINUTES OF DAYLIGHT | HIGH TEMP °C |
3 | WINTER YEAR 1 | 161 | 21 | 11 hr 56.12 min | -3 |
4 | WINTER YEAR 1 | 162 | 22 | 11 hr 56.40 min | -6 |
5 | WINTER YEAR 1 | 166 | 30 | 11 hr 57.50 min | -3 |
11 | WINTER YEAR 1 | 179 | 52 | 12 hr 1.12 min | -7 |
30 | WINTER YEAR 2 | 165 | 697 | 11 hr 57.21 min | -4 |
31 | WINTER YEAR 2 | 178 | 720 | 12 hr 0.84 min | -1 |
32 | WINTER YEAR 2 | 179 | 722 | 12 hr 1.12 min | 1 |