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Lake Malawi Temperature

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  • Jesse Johnson
    All, Here is some interesting perspective on drought/temperature fluctuation in Malawi. See attached plot. Data source info below. To me it says that there has
    Message 1 of 4 , Nov 14, 2005
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      All,

      Here is some interesting perspective on drought/temperature fluctuation
      in Malawi. See attached plot. Data source info below.

      To me it says that there has never really been a period of agricultural
      stability in Malawi (and likely beyond, to much of sub-Saharan Africa).
      Then again, other proxies (tree rings, coral, stalagmites,
      boreholes,glaciers) show considerable (but not as much) fluctuation in
      Europe and Asia. However, I do not know of a record that is as long and
      as well validated as this one for Malawi.

      It's a tough place to live, Malawi.

      Jesse


      Lake Malawi TEX86 Surface Temperature Reconstruction
      -----------------------------------------------------------------------
      World Data Center for Paleoclimatology, Boulder
      and
      NOAA Paleoclimatology Program
      -----------------------------------------------------------------------
      NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!!

      NAME OF DATA SET: Lake Malawi TEX86 Surface Temperature Reconstruction
      LAST UPDATE: 4/2005 (Original receipt by WDC Paleo)

      CONTRIBUTORS:
      Lindsay A. Powers, Thomas C. Johnson, Josef P. Werne, Isla S. Castañeda,
      Ellen C. Hopmans, Jaap S. Sinninghe Damsté and Stefan Schouten

      IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2005-038

      SUGGESTED DATA CITATION: Powers, L.A., et al.. 2005.
      Lake Malawi TEX86 Surface Temperature Reconstruction.
      IGBP PAGES/World Data Center for Paleoclimatology
      Data Contribution Series # 2005-038.
      NOAA/NCDC Paleoclimatology Program, Boulder CO, USA.


      ORIGINAL REFERENCE:
      Powers, L.A., T.C. Johnson, J.P. Werne, I.S. Castañeda, E.C. Hopmans,
      J.S. Sinninghe Damsté, and S. Schouten. 2005.
      Large temperature variability in the southern African tropics since
      the Last Glacial Maximum.
      Geophysical Research Letters, 32, L08706, doi:10.1029/2004GL022014.

      ABSTRACT:
      The role of the tropics in global climate change is actively debated,
      particularly in regard to the timing and magnitude of thermal and
      hydrological response. Continuous, high-resolution temperature records
      through the Last Glacial Maximum (LGM) from tropical oceans have
      provided much insight but surface temperature reconstructions do not
      exist from tropical continental environments. Here we used the TEX86
      paleotemperature proxy to reconstruct mean annual lake surface
      temperatures through the Last Glacial Maximum (LGM) in Lake Malawi,
      East Africa (9º-14ºS). We find a ~3.5ºC overall warming since the LGM,
      with temperature reversals of ~ 2ºC during the Younger Dryas (12.5 ka BP)
      and at 8.2 ka BP. Maximum Holocene temperatures of ~29ºC were found
      at 5 ka BP, a period preceding severe drought in Africa. These results
      suggest a substantial thermal response of southeastern tropical Africa
      to deglaciation and to varying conditions during the Holocene.


      GEOGRAPHIC REGION: Tropical East Africa
      PERIOD OF RECORD: 24 KYrBP - present

      FUNDING SOURCES:
      National Science Foundation (USA) grants ATM-9709291 and ATM-0081776 (to TCJ),
      and a European Association of Organic Geochemists travel scholarship to LAP.

      DESCRIPTION:
      The dataset is a paleotemperature reconstruction of mean annual surface
      temperature from the north basin of Lake Malawi, East Africa using the
      TEX86 paleothermometer. (TetraEther indeX of tetraethers with 86 carbon atoms).
      The age model for these cores is already available for previous Lake Malawi MP98
      data sets on this website.

      TEX86 values are means of replicate analyses. All samples were measured at least
      in duplicate, half of samples were measured at least in triplicate. The calibration
      equation used to calculate mean annual lake surface temperatures (LST) is
      LST=(TEX86-0.25)/0.017 with a calibration error of +/- 2 degrees C.

      Lake Malawi core M98-1P: 10º15.9'S, 34º19.1'E, water depth 403m.
      Lake Malawi core M98-2P: 9º58.6'S, 34º13.8'E, water depth 363m.
      Lake surface elevation 474m.



      DATA:
      Lake Malawi TEX86 Surface Temperature Reconstruction

      Column 1: Age, cal kYBP
      Column 2: TEX86, means of replicate analyses
      Column 3: Mean Temperature
      Column 4: Standard Deviation

      Age TEX86 Temp SD
      0.25 0.69 25.88 0.86
      0.57 0.69 26.17 0.19
      1.75 0.71 26.87 0.76
      2.96 0.69 26.16 0.71
      3.32 0.7 26.6 0.21
      3.54 0.7 26.71 0.43
      4.23 0.72 27.79 0.45
      4.45 0.72 27.49 0.56
      4.77 0.73 28.52 0.46
      5.05 0.74 28.93 0.58
      5.46 0.74 28.61 0.02
      6.22 0.72 27.6 0.11
      6.72 0.72 27.58 0.22
      7.45 0.68 25.06 0.78
      7.58 0.69 25.91 0.56
      7.79 0.68 25.09 0.25
      8.02 0.69 25.81 0.02
      8.23 0.66 24.35 0.23
      8.92 0.69 26.17 0.67
      10.23 0.69 25.85 0.71
      10.9 0.68 25.52 0.49
      11.46 0.7 26.44 0.78
      11.94 0.7 26.6 0.64
      12.2 0.69 25.84 0.12
      12.51 0.68 25.3 0.14
      12.72 0.68 25.48 0.55
      12.98 0.71 27.13 0.28
      13.52 0.69 25.64 0.18
      13.74 0.72 27.49 0.08
      13.84 0.73 28.15 0.55
      14.29 0.71 27 0.06
      14.51 0.7 26.37 0.65
      14.89 0.69 25.86 0.66
      15.94 0.67 24.97 0.57
      17.58 0.65 23.48 0.77
      18.52 0.64 23.09 0.83
      19.01 0.64 23.13 0.74
      20.01 0.63 22.58 0.58
      20.78 0.63 22.52 0.43
      21.77 0.66 23.98 0.3
      22.43 0.66 24.13 0.01
      23.24 0.67 24.48 0.58
      23.88 0.66 24.19 0.03


      --
      Jesse Johnson, Assistant Professor
      Department of Computer Science
      Social Science Building, Room 417
      The University of Montana
      Missoula, MT 59812-5256

      tel: (406) 243-2356
      fax: (406) 243-5139

      email: johnson@...
      web: http://www.cs.umt.edu/u/johnson
    • Don & Cathy Weber
      Julie, Richa, Ally, and Kim...Re: Photo. Do recognize your house as it was June 2004? Glad we knew where to look or we sure wouldn t have. _______ Jesse, As
      Message 2 of 4 , Nov 14, 2005
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        Julie, Richa, Ally, and Kim...Re: Photo.  Do recognize your house as it was June 2004?  Glad we knew where to look or we sure wouldn't have. 
        _______
         
        Jesse,
         
        As always you're information is really intriguing though quite overwhelming.  So I have this question.  I listen to these guys on NPR a lot, this time a BBC program I'm sure.  This Brit...unfortunately my mind tuned in after they said who he was, most assuredly government...said that with climate changes, sub Saharan Africa is going to continue to face droughts.  And because of that, all the aid money available will have to go to famine relief instead of development.  In view of what you are saying, does it prove or disprove his predictions...that graph is in years x 1000, right?   So how does one know ... appears that we are in a just a moderately high temperature period.  But you can't predict much of anything from it can you?  Look how variable.  And how can you even graph a beginning spike on a "years x 1,000" graph?  I'm an older woman; I'm allowed, actually expected, to be stupid about these things.
         
        What was climate like 5,000 years ago when lake temps were considerably higher?   Does temp increase always bring drought to Africa?   If so, I guess with fewer people and different ways of obtaining food, drought would not have been so critical.  Seems, if one reads Stacia Norden's comments about diversifying and thinking of more drought hardy crops, those changes might help, that is if we are in an upward temperature and drying trend.  Change is hard, and I must admit that lump of nsima made me feel satisfied with little else to go with it. 
         
        You're right.  "It's a tough place to live, Malawi."
         
        Cathy
         
         

      • Jesse Johnson
        Hi Cathy, Well, I was attracted to that article because it is recent (2005), and deals with Malawi. I have fun thinking about a bunch of geophysicists trying
        Message 3 of 4 , Nov 16, 2005
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          Hi Cathy,

          Well, I was attracted to that article because it is recent (2005), and
          deals with Malawi. I have fun thinking about a bunch of geophysicists
          trying to acquire a lake core in Malawi.

          Then I started thinking about the data. It shows huge changes in
          temperature. I don't think one can say, oh, it's hot, that means
          drought, or vice versa. But what you can say (I think) is that there are
          giant swings on a scale of thousands of years. If anything, lakes have
          a calming effect on big swings (all that water doesn't like to change
          its temperature), away from the lake it was likely even worse.

          Thousands of years, thats the kind of time one needs to do things like;
          domesticate a chicken, selectively breed crops to get higher yields,
          find ways to store harvests, or just identify good species to focus on.
          Well, about the time you start to make headway on any of that, you are
          suddenly living in another world, climate wise.

          And what you really need, if your going to develop science, religion,
          arts, and culture, government and law, what you really need, is
          agricultural stability.

          This graph shows that (probably) Southern Africa never got that.

          And maybe (maybe) that is part of why Africa is the way it is.

          Maybe. It's a question I can't stop thinking about.

          Good to hear from you. Attached is a photo of the boys. They are about
          to participate in this great Montana tradition, hunting. Just driving
          around really, looking out of a truck for elk. This is part of how we
          get on with the neighbors. But they do love to get dressed up.

          Jesse
        • Daniel Dudley
          God, Jessie, the kids look GREAT!!! Nice article that you sent around, and thoughts here, interesting to think about. Can you send me a link where I can get
          Message 4 of 4 , Nov 18, 2005
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            God, Jessie, the kids look GREAT!!! Nice article that you sent around, and
            thoughts here, interesting to think about. Can you send me a link where I
            can get some information on that science thing that you did last year, I
            have a student that may be interested!!!

            Dan


            >From: Jesse Johnson <johnson@...>
            >Reply-To: ujeni@yahoogroups.com
            >To: ujeni@yahoogroups.com
            >Subject: Re: [ujeni] Lake Malawi Temperature
            >Date: Thu, 17 Nov 2005 00:25:19 -0700
            >
            >Hi Cathy,
            >
            >Well, I was attracted to that article because it is recent (2005), and
            >deals with Malawi. I have fun thinking about a bunch of geophysicists
            >trying to acquire a lake core in Malawi.
            >
            >Then I started thinking about the data. It shows huge changes in
            >temperature. I don't think one can say, oh, it's hot, that means
            >drought, or vice versa. But what you can say (I think) is that there are
            >giant swings on a scale of thousands of years. If anything, lakes have
            >a calming effect on big swings (all that water doesn't like to change
            >its temperature), away from the lake it was likely even worse.
            >
            >Thousands of years, thats the kind of time one needs to do things like;
            >domesticate a chicken, selectively breed crops to get higher yields,
            >find ways to store harvests, or just identify good species to focus on.
            >Well, about the time you start to make headway on any of that, you are
            >suddenly living in another world, climate wise.
            >
            >And what you really need, if your going to develop science, religion,
            >arts, and culture, government and law, what you really need, is
            >agricultural stability.
            >
            >This graph shows that (probably) Southern Africa never got that.
            >
            >And maybe (maybe) that is part of why Africa is the way it is.
            >
            >Maybe. It's a question I can't stop thinking about.
            >
            >Good to hear from you. Attached is a photo of the boys. They are about
            >to participate in this great Montana tradition, hunting. Just driving
            >around really, looking out of a truck for elk. This is part of how we
            >get on with the neighbors. But they do love to get dressed up.
            >
            >Jesse
            >
            >
            >
            >
            >
            >Yahoo! Groups Links
            >
            >
            >
            >


            ><< hunt.jpg >>
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