Weather below sealevel

[kennymoens]

Hi Pete,

When using the FSUIPC NWI we came to the conlusion that setting weather (temperature layers, cloud layers,...) below sealevel causes problems in FSUIPC.

The extract from the fsuipc.log:

   135125 >NewSet:  Temperature[0]: alt=214977ft, Day=3 C, NightVar=0 C, DewPt=4 C
   135125 >NewSet:  Temperature[1]: alt=2999ft, Day=4 C, NightVar=0 C, DewPt=5 C
   135125 >NewSet:  Temperature[2]: alt=6001ft, Day=2 C, NightVar=0 C, DewPt=3 C
   135125 >NewSet:  Temperature[3]: alt=8999ft, Day=-1 C, NightVar=0 C, DewPt=0 C
   135125 >NewSet:  Temperature[4]: alt=12001ft, Day=-9 C, NightVar=0 C, DewPt=-8 C
   135125 >NewSet:  Temperature[5]: alt=17999ft, Day=-19 C, NightVar=0 C, DewPt=-18 C
   135125 >NewSet:  Temperature[6]: alt=23999ft, Day=-33 C, NightVar=0 C, DewPt=-32 C
   135125 >NewSet:  Temperature[7]: alt=30000ft, Day=-50 C, NightVar=0 C, DewPt=-49 C
   135125 >NewSet:  Temperature[8]: alt=33999ft, Day=-59 C, NightVar=0 C, DewPt=-58 C
   135125 >NewSet:  Temperature[9]: alt=38999ft, Day=-67 C, NightVar=0 C, DewPt=-66 C
   135125 >NewSet:  Surface wind: to alt=2238ft AMSL, dir=200T, vel=9.00, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 1: to alt=2999ft AMSL, dir=198T, vel=18.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 2: to alt=6001ft AMSL, dir=224T, vel=10.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 3: to alt=8999ft AMSL, dir=228T, vel=9.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 4: to alt=12001ft AMSL, dir=221T, vel=11.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 5: to alt=17999ft AMSL, dir=200T, vel=19.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 6: to alt=23999ft AMSL, dir=194T, vel=20.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 7: to alt=30000ft AMSL, dir=186T, vel=19.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 8: to alt=33999ft AMSL, dir=205T, vel=12.0, gust=0.0, turb=0, shear=0, var=0.0
   135125 >NewSet:  Wind layer 9: to alt=38999ft AMSL, dir=261T, vel=15.0, gust=0.0, turb=0, shear=0, var=0.0

And the same part from our logs:

[2005-01-16 16:05] Weather: icao = EHAM, general, qnh = 1021.000000, windlayers = 10, cloudlayers = 0, templayers = 10
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 682 m, spd = 9.000000 kts, gusts = 0 kts, dir = 200 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 914 m, spd = 18.000000 kts, gusts = 0 kts, dir = 198 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 1829 m, spd = 10.000000 kts, gusts = 0 kts, dir = 224 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 2743 m, spd = 9.000000 kts, gusts = 0 kts, dir = 228 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 3658 m, spd = 11.000000 kts, gusts = 0 kts, dir = 221 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 5486 m, spd = 19.000000 kts, gusts = 0 kts, dir = 200 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 7315 m, spd = 20.000000 kts, gusts = 0 kts, dir = 194 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 9144 m, spd = 19.000000 kts, gusts = 0 kts, dir = 186 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 10363 m, spd = 12.000000 kts, gusts = 0 kts, dir = 205 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, wind, alt = 11887 m, spd = 15.000000 kts, gusts = 0 kts, dir = 261 °, var = 0 °, turbulence = 0, windshear = 0
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = -11 m, temp = 3.000000 °C, var = 0.000000 °C, dewpoint = 4.000000 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 914 m, temp = 4.900000 °C, var = 0.000000 °C, dewpoint = 5.900000 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 1829 m, temp = 2.900000 °C, var = 0.000000 °C, dewpoint = 3.900000 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 2743 m, temp = -1.000000 °C, var = 0.000000 °C, dewpoint = 0.000000 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 3658 m, temp = -9.200000 °C, var = 0.000000 °C, dewpoint = -8.200000 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 5486 m, temp = -19.299999 °C, var = 0.000000 °C, dewpoint = -18.299999 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 7315 m, temp = -33.700001 °C, var = 0.000000 °C, dewpoint = -32.700001 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 9144 m, temp = -50.900002 °C, var = 0.000000 °C, dewpoint = -49.900002 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 10363 m, temp = -59.400002 °C, var = 0.000000 °C, dewpoint = -58.400002 °C
[2005-01-16 16:05] Weather: icao = EHAM, temp, alt = 11887 m, temp = -67.699997 °C, var = 0.000000 °C, dewpoint = -66.699997 °C
[2005-01-16 16:05] Weather: icao = EHAM, visibility, visibility = 5592 m, base = 0 m, top = 54 m

We checked the modules for the NWI and it seems that an unsigned short has to be passed as altitude in all cases, this probably thus causes the overflow we experience in the logs above.

My questions now :

1) Is it at all possible with FSUIPC to set layers below sealevel? (EHAM is an example of an airport below sealevel)

2) Is this due an FS limitation or can it be fixed in FSUIPC?

If this question has been asked in the past, I'm sorry for posting it then.

Thanks,

[Pete Dowson]

When using the FSUIPC NWI we came to the conlusion that setting weather (temperature layers, cloud layers,...) below sealevel causes problems in FSUIPC.

Can you actually set such layers in FS? Certainly the altitudes I deal with are positive only (except the Precipitation Base, to allow rain to reach the ground!).

This doesn't mean that there will be no weather below sea level, as the layer levels, excepting cloudbases, are notional, and even with cloudbases you can set the deviation so you get parts lower.

The temperatures, for instance, do scale appropriately all the way up and down between the "layer levels".

Easiest thing to do, in your program, is check altitude < 0 and if so set it to 0 before supplying it to FSUIPC. Does this cause any unwanted results? Maybe I'm not understanding something you are wanting to do?

Regards,

Pete

[kennymoens]

So stupid of me not to check if the FS default weather settings allow negative altitudes, I guess I've been programming too long the last days :lol:

Tests yesterday with using 0 as altitude for temperature seemed to give the correct results, we didn't had time yet to check if it was correct for the others.

The other information you gave us seems interesting too, thank you for you help.

Greetz