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Outside Air Temp vs. Altitude

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  • Zack Clobes
    During the last chase we were discussing why the temperature was climbing up near the burst altitude. www.rckara.org/temp/2001b.pdf The above link is to a
    Message 1 of 11 , Oct 2, 2005
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      During the last chase we were discussing why the temperature was
      climbing up near the burst altitude.

      www.rckara.org/temp/2001b.pdf

      The above link is to a graph that I produced after our 2001b launch show
      the temperature rising back up to nearly freezing level at burst. The
      launch was in August of 2001. We haven't flown the OAT sensor very
      much, so this may be our only chart of the data, but many other groups
      should have similar data.

      I'm curious how these temperatures vary throughout the year...

      Zack Clobes, W0ZC
      Project: Traveler
    • Paulus Adisoemarta
      ... Concur! We also observe the same response on flight 2005C of August 6th 2005, here is the link to the temperature plot:
      Message 2 of 11 , Oct 2, 2005
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        According to Zack Clobes:
        >
        >During the last chase we were discussing why the temperature was
        >climbing up near the burst altitude.
        >
        >www.rckara.org/temp/2001b.pdf
        >
        >The above link is to a graph that I produced after our 2001b launch show
        >the temperature rising back up to nearly freezing level at burst. The
        >launch was in August of 2001. We haven't flown the OAT sensor very
        >much, so this may be our only chart of the data, but many other groups
        >should have similar data.

        Concur!
        We also observe the same response on flight 2005C of August 6th 2005,
        here is the link to the temperature plot:
        http://www.arsat.org/gallery/ARSAT-Space-Flight/Temperature


        73 de Paulus N5SNN
        --
        Paulus Suryono Adisoemarta, Ph.D.
        Assistant Professor
        Petroleum Engineering Dept. paulus@...
        Texas Tech University, Lubbock TX N5SNN / YG1QN
      • Zack Clobes
        Do you have any data from other months of the year?
        Message 3 of 11 , Oct 2, 2005
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          Do you have any data from other months of the year?

          Paulus Adisoemarta wrote:
          According to Zack Clobes:
            
          During the last chase we were discussing why the temperature was 
          climbing up near the burst altitude.
          
          www.rckara.org/temp/2001b.pdf
          
          The above link is to a graph that I produced after our 2001b launch show 
          the temperature rising back up to nearly freezing level at burst.  The 
          launch was in August of 2001.  We haven't flown the OAT sensor very 
          much, so this may be our only chart of the data, but many other groups 
          should have similar data.
              
          Concur!
          We also observe the same response on flight 2005C of August 6th 2005,
          here is the link to the temperature plot:
          http://www.arsat.org/gallery/ARSAT-Space-Flight/Temperature
          
          
          73 de Paulus N5SNN
            
        • mgray@ess-us.com
          Out of Arizona: April 2005 http://www.kd7lmo.net/ansr_24_data.html Jan 2005 - Night http://www.kd7lmo.net/ansr_22_data.html April 2004
          Message 4 of 11 , Oct 2, 2005
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            Out of Arizona:

            April 2005

            http://www.kd7lmo.net/ansr_24_data.html


            Jan 2005 - Night

            http://www.kd7lmo.net/ansr_22_data.html


            April 2004

            http://www.kd7lmo.net/ansr_18_charts.html


            March 2004

            http://www.kd7lmo.net/ansr_17_charts.html


            You can also download data in CSV format that has OAT for our flight over
            the last few years.

            http://www.kd7lmo.net/ansr.html


            Good luck with your projects




            On Sun, 2 Oct 2005, Zack Clobes wrote:

            > Do you have any data from other months of the year?
            >
            > Paulus Adisoemarta wrote:
            >
            > >According to Zack Clobes:
            > >
            > >
            > >>During the last chase we were discussing why the temperature was
            > >>climbing up near the burst altitude.
            > >>
            > >>www.rckara.org/temp/2001b.pdf
            > >>
            > >>The above link is to a graph that I produced after our 2001b launch show
            > >>the temperature rising back up to nearly freezing level at burst. The
            > >>launch was in August of 2001. We haven't flown the OAT sensor very
            > >>much, so this may be our only chart of the data, but many other groups
            > >>should have similar data.
            > >>
            > >>
            > >
            > >Concur!
            > >We also observe the same response on flight 2005C of August 6th 2005,
            > >here is the link to the temperature plot:
            > >http://www.arsat.org/gallery/ARSAT-Space-Flight/Temperature
            > >
            > >
            > >73 de Paulus N5SNN
            > >
            > >
            >
          • Ralph Wallio, W0RPK
            Long term averages of temperature increase with altitude above the tropopause as can be seen in U.S. Standard Atmosphere (see http://www.pdas.com/atmos.htm).
            Message 5 of 11 , Oct 3, 2005
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              Long term averages of temperature increase with altitude above the
              tropopause as can be seen in U.S. Standard Atmosphere (see
              http://www.pdas.com/atmos.htm). At the tropopause, 11.1-20.0km, USSA
              is -56.5dC. Temperature then increases to a maximum of -2.5dC, 47.4-51.0km,
              and then starts back down all the way to the top of USSA, -85.23dC at
              85.5km.

              These averages are broken down by latitude and month-of-year in Global
              Atmospheric Circulation Statistics, 1000-1mb, NCAR Technical Note 366 (the
              same NCAR/TN I discuss in http://showcase.netins.net/web/wallio/MZW.html -
              Mean Zonal Winds). Down in the banana belt at 35dN the averages for 10mb
              (31.2km) vary -45 to -36dC, winter to summer.

              From these averages it appears ARHAB temperature measurements approaching
              0dC at typical burst altitude are roughly 40dC high. So what could be the
              problem(?) Lets assume sensor calibration at the surface is correct when
              directly illuminated by the sun where Atmospheric Mass = 1.5 (AM1.5). Is it
              still correct at altitude when illuminated at AM0 (with no atmospheric
              attenuation)(?).

              TNX es 73 de Ralph Wallio, W0RPK
              W0RPK@...
              http://showcase.netins.net/web/wallio/
              Hubbert's Peak - The Mother of all Perfect Storms
            • n9xtn@cox.net
              Most all atmospheric temperature sensors are designed to be shielded from sunlight for proper operation. If you are operating a LM335-type sensor, for best
              Message 6 of 11 , Oct 3, 2005
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                Most all atmospheric temperature sensors are designed to be shielded
                from sunlight for proper operation. If you are operating a LM335-type
                sensor, for best results it should be placed in something that
                provides free air flow over the sensor yet blocks the sun. I made a
                quick housing for mine out of a block of foam with a hole cut
                lengthwise through the middle that is oriented vertically on the
                payload (the sensor is attached so it is in about the center of the
                block). Even with this design, our temperatures run higher than the
                radiosonde temps above 60 kft, so it's still not perfect.

                Based on NSTAR's flight experience, the sun provides a lot of warming
                at high altitudes. The combination of more intense sunlight due to
                less atmospheric attenuation, plus (more importantly) far less heat
                carried away by convection in the thin atmosphere leads to heating
                above the ambient temperature. Once the sun goes away, temperatures
                will drop off dramatically.

                From Saturday morning's sounding at Topeka, the temperature at 107,000
                ft (highest altitude reported) was -45°C.

                http://weather.uwyo.edu/cgi-bin/sounding?region=naconf&TYPE=TEXT%
                3ALIST&YEAR=2005&MONTH=10&FROM=0112&TO=0112&STNM=72456


                73 de Mark N9XTN

                ----- Original Message -----
                From: "Ralph Wallio, W0RPK" <W0RPK@...>
                Date: Monday, October 3, 2005 7:14 am
                Subject: Re: [GPSL] Outside Air Temp vs. Altitude


                > From these averages it appears ARHAB temperature measurements
                > approaching
                > 0dC at typical burst altitude are roughly 40dC high. So what
                > could be the
                > problem(?) Lets assume sensor calibration at the surface is
                > correct when
                > directly illuminated by the sun where Atmospheric Mass = 1.5
                > (AM1.5). Is it
                > still correct at altitude when illuminated at AM0 (with no
                > atmospheric
                > attenuation)(?).
              • PAUL VERHAGE
                I ve run tests on temperatures and color in near space. I can warm up a 2 inch cube by 10 degrees (or more) by painting it black. Surprisingly though, the
                Message 7 of 11 , Oct 3, 2005
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                  I've run tests on temperatures and color in near space. I can warm up a 2 inch cube by 10 degrees (or more) by painting it black.

                  Surprisingly though, the aluminum block was cooler than the black one. I understood that aluminum had a high reflectivity, but low emissivity. The net result being that once heat got into the aluminum, it was difficult for it to get out. This si why we cover potatoes in aluminum foil.

                  Paul

                  >>> n9xtn@... 10/03/05 8:14 AM >>>
                  Most all atmospheric temperature sensors are designed to be shielded
                  from sunlight for proper operation. If you are operating a LM335-type
                  sensor, for best results it should be placed in something that
                  provides free air flow over the sensor yet blocks the sun. I made a
                  quick housing for mine out of a block of foam with a hole cut
                  lengthwise through the middle that is oriented vertically on the
                  payload (the sensor is attached so it is in about the center of the
                  block). Even with this design, our temperatures run higher than the
                  radiosonde temps above 60 kft, so it's still not perfect.

                  Based on NSTAR's flight experience, the sun provides a lot of warming
                  at high altitudes. The combination of more intense sunlight due to
                  less atmospheric attenuation, plus (more importantly) far less heat
                  carried away by convection in the thin atmosphere leads to heating
                  above the ambient temperature. Once the sun goes away, temperatures
                  will drop off dramatically.

                  From Saturday morning's sounding at Topeka, the temperature at 107,000
                  ft (highest altitude reported) was -45°C.

                  http://weather.uwyo.edu/cgi-bin/sounding?region=naconf&TYPE=TEXT%
                  3ALIST&YEAR=2005&MONTH=10&FROM=0112&TO=0112&STNM=72456


                  73 de Mark N9XTN

                  ----- Original Message -----
                  From: "Ralph Wallio, W0RPK" <W0RPK@...>
                  Date: Monday, October 3, 2005 7:14 am
                  Subject: Re: [GPSL] Outside Air Temp vs. Altitude


                  > From these averages it appears ARHAB temperature measurements
                  > approaching
                  > 0dC at typical burst altitude are roughly 40dC high. So what
                  > could be the
                  > problem(?) Lets assume sensor calibration at the surface is
                  > correct when
                  > directly illuminated by the sun where Atmospheric Mass = 1.5
                  > (AM1.5). Is it
                  > still correct at altitude when illuminated at AM0 (with no
                  > atmospheric
                  > attenuation)(?).





                  Yahoo! Groups Links
                • Mike Manes
                  Hi Zack, That s the tropopause you re seeing - the interface between the troposphere and the stratosphere. And yeah, the first time I saw that, I thought we d
                  Message 8 of 11 , Oct 3, 2005
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                    Hi Zack,

                    That's the tropopause you're seeing - the interface between the
                    troposphere and the stratosphere. And yeah, the first time I saw
                    that, I thought we'd had an instrumentation problem.

                    All of the "weather" we experience occurs in the troposphere, where
                    the air density is high enough to promote significant convection.
                    Above that, the air temp increases due to reduced solar flux
                    attenuation,
                    lack of significant convection and, of course, very low thermal mass.

                    The elevation of the tropopause varies from above 60K' in the summer
                    down to under 30K' in the winter.

                    One thing to watch out for with OAT sensors: the low air density at
                    altitude restricts heat transfer between the temp sensor and the air.
                    If there's any self-heating in the sensor, then it'll read high.
                    Especially during the 1000 fpm ascent. But after burst, when your
                    airspeed gets near-Mach-ish, that heat transfer improves dramatically.
                    Thus, you're likely to a much lower OAT vs Alt curve during descent
                    than during ascent. You can minimize this error by putting a thin
                    heatsink on the sensor, exposed to full ambient airflow, but also
                    shielded from solar heating (tough trick, but check how radiosondes
                    do it).

                    Kewl science for your kids, huh?

                    73 de Mike W5VSI

                    Zack Clobes wrote:
                    >
                    > During the last chase we were discussing why the temperature was
                    > climbing up near the burst altitude.
                    >
                    > www.rckara.org/temp/2001b.pdf
                    >
                    > The above link is to a graph that I produced after our 2001b launch show
                    > the temperature rising back up to nearly freezing level at burst. The
                    > launch was in August of 2001. We haven't flown the OAT sensor very
                    > much, so this may be our only chart of the data, but many other groups
                    > should have similar data.
                    >
                    > I'm curious how these temperatures vary throughout the year...
                    >
                    > Zack Clobes, W0ZC
                    > Project: Traveler
                    >
                    >
                    >
                    > Yahoo! Groups Links
                    >
                    >
                    >
                    >

                    --
                    Mike Manes manes@... Tel: 303-979-4899
                    "Things should be made as simple as possible, but not more so." A.
                    Einstein
                  • Mike Manes
                    Hi Paul, At optical wavelengths, Al does have high R and thus low E, i.e., it s bright-looking. But at IR, the opposite is true! Same is true for Chromium -
                    Message 9 of 11 , Oct 3, 2005
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                      Hi Paul,

                      At optical wavelengths, Al does have high R and thus low E, i.e., it's
                      bright-looking. But at IR, the opposite is true! Same is true for
                      Chromium - which is why chrome trim on a car sitting out in bright
                      sunlight can burn you. Similarly, a black anodized heatsink is not
                      much more effective at far-IR radiative wavelengths than is bare Al
                      surface.

                      If you really need a good solar absorber/emitter, use carbon black
                      based paint. As close to a pure thermal "black body" as you can get
                      from local sources.

                      73 de Mike W5VSI



                      PAUL VERHAGE wrote:
                      >
                      > I've run tests on temperatures and color in near space. I can warm up a 2 inch cube by 10 degrees (or more) by painting it black.
                      >
                      > Surprisingly though, the aluminum block was cooler than the black one. I understood that aluminum had a high reflectivity, but low emissivity. The net result being that once heat got into the aluminum, it was difficult for it to get out. This si why we cover potatoes in aluminum foil.
                      >
                      > Paul
                      >
                      > >>> n9xtn@... 10/03/05 8:14 AM >>>
                      > Most all atmospheric temperature sensors are designed to be shielded
                      > from sunlight for proper operation. If you are operating a LM335-type
                      > sensor, for best results it should be placed in something that
                      > provides free air flow over the sensor yet blocks the sun. I made a
                      > quick housing for mine out of a block of foam with a hole cut
                      > lengthwise through the middle that is oriented vertically on the
                      > payload (the sensor is attached so it is in about the center of the
                      > block). Even with this design, our temperatures run higher than the
                      > radiosonde temps above 60 kft, so it's still not perfect.
                      >
                      > Based on NSTAR's flight experience, the sun provides a lot of warming
                      > at high altitudes. The combination of more intense sunlight due to
                      > less atmospheric attenuation, plus (more importantly) far less heat
                      > carried away by convection in the thin atmosphere leads to heating
                      > above the ambient temperature. Once the sun goes away, temperatures
                      > will drop off dramatically.
                      >
                      > >From Saturday morning's sounding at Topeka, the temperature at 107,000
                      > ft (highest altitude reported) was -45°C.
                      >
                      > http://weather.uwyo.edu/cgi-bin/sounding?region=naconf&TYPE=TEXT%
                      > 3ALIST&YEAR=2005&MONTH=10&FROM=0112&TO=0112&STNM=72456
                      >
                      > 73 de Mark N9XTN
                      >
                      > ----- Original Message -----
                      > From: "Ralph Wallio, W0RPK" <W0RPK@...>
                      > Date: Monday, October 3, 2005 7:14 am
                      > Subject: Re: [GPSL] Outside Air Temp vs. Altitude
                      >
                      > > From these averages it appears ARHAB temperature measurements
                      > > approaching
                      > > 0dC at typical burst altitude are roughly 40dC high. So what
                      > > could be the
                      > > problem(?) Lets assume sensor calibration at the surface is
                      > > correct when
                      > > directly illuminated by the sun where Atmospheric Mass = 1.5
                      > > (AM1.5). Is it
                      > > still correct at altitude when illuminated at AM0 (with no
                      > > atmospheric
                      > > attenuation)(?).
                      >
                      >
                      > Yahoo! Groups Links
                      >
                      >
                      >
                      >
                      >
                      > Yahoo! Groups Links
                      >
                      >
                      >
                      >

                      --
                      Mike Manes manes@... Tel: 303-979-4899
                      "Things should be made as simple as possible, but not more so." A.
                      Einstein
                    • Hank Riley
                      Zack, Could you describe your temperature sensor for us? Size, color, whether enclosed or shaded from sun. Links to pictures if available, too. Hank
                      Message 10 of 11 , Oct 4, 2005
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                        Zack,

                        Could you describe your temperature sensor for us?
                        Size, color, whether enclosed or shaded from sun.

                        Links to pictures if available, too.

                        Hank



                        __________________________________
                        Yahoo! Mail - PC Magazine Editors' Choice 2005
                        http://mail.yahoo.com
                      • Zack Clobes
                        Uhhhh.... I dunno. That was four years ago.. :-) I m using the ?LM-35CTZ? (or thereabouts) temp sensor. For external temps, I was using the one rated down to
                        Message 11 of 11 , Oct 4, 2005
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                          Uhhhh.... I dunno. That was four years ago.. :-)

                          I'm using the ?LM-35CTZ? (or thereabouts) temp sensor. For external
                          temps, I was using the one rated down to -55C. As I recall, I put the
                          whole sensor including the solder joints into a sleeve of black heat-shrink.

                          The sensor was designed to just hang from the three wires, probably out
                          of the lid, but I don't recall precisely. My guess is that it was
                          exposed to sunlight.

                          Zack Clobes, W0ZC
                          Project: Traveler

                          Hank Riley wrote:

                          >Zack,
                          >
                          >Could you describe your temperature sensor for us?
                          >Size, color, whether enclosed or shaded from sun.
                          >
                          >Links to pictures if available, too.
                          >
                          >Hank
                          >
                          >
                          >
                          >__________________________________
                          >Yahoo! Mail - PC Magazine Editors' Choice 2005
                          >http://mail.yahoo.com
                          >
                          >
                          >
                          >
                          >Yahoo! Groups Links
                          >
                          >
                          >
                          >
                          >
                          >
                          >
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