КОЛИЧЕСТВЕННЫЕ И КАЧЕСТВЕННЫЕ ОГРАНИЧЕНИЯ ПО РЕТРОСПЕКТИВНЫМ ФОРМИРОВАНИЕ МНОГОЛЕТНЕГО

КОЛИЧЕСТВЕННЫЕ И КАЧЕСТВЕННЫЕ ОГРАНИЧЕНИЯ ПО РЕТРОСПЕКТИВНЫМ ФОРМИРОВАНИЕ МНОГОЛЕТНЕГО ОЗЕРА ЛЕДЯНОГО ПОКРОВА НА ОЗЕРЕ ЭЛЬГЫГЫТГЫН M. Nolan Университет Аляски (США) Опубликовано: 19 июня 2013

PRECIPITATION AT LAKE EL’GYGYTGYN. IN (A), CUMULATIVE RAINFALL FROM THE AWS TIPPING BUCKET (THICK LINES) AND NNR (THICK LINES). THE NNR FAILS TO CAPTURE DAILY EVENTS, BUT DOES BETTER IN CAPTURING ANNUAL TRENDS, THOUGH 2– 3 TIMES HIGHER IN MAGNITUDE. IN (B), ANNUAL PRECIPITATION FROM NNR, SHOWING THAT WINTER AND SUMMER MAGNITUDES ARE ROUGHLY EQUAL, AND DRY IN GENERAL.

AIR TEMPERATURE ATLAKE EL’GYGYTGYN. IN (A), MEAN ANNUAL AIR TEMPERATURE AND DEGREE DAYS FROM NNR (THICK LINES) AND AWS (THIN LINES), SHOWING THAT NNR CAPTURES THE AWS TRENDS WELL AND MAGNITUDE BEST IN SUMMER, WHICH IS MOST IMPORTANT TO OUR STUDY. DUE TO THE PRONOUNCED WARMING TREND STARTING IN THE LATE-1980 S, WE USED THE PERIOD 1961– 1988 TO DEFINE THE MODERN ERA USED IN THIS STUDY. IN (B), DAILY NNR IS COMPARED TO LOCAL AWS SHOWING THAT THE TRENDS AND MAGNITUDE ARE CAPTURED WELL, THOUGHNNR FAILS TO CAPTURE THE COLDEST TEMPERATURES, CAUSING ABOUT AVERAGE. 1◦ OF MISFIT ON C

NNR DAILY MINIMUM, MAXIMUM, AND MEAN FOR 1961– 1988. THIS MEAN IS WHAT WE USED FOR THE “MODERN” ERA IN COMPARISONS WITH PALEOCONDITIONS.

MODEL OUTPUT FOR THENNR RECORD 1961– 2009. IN (A), MAXIMUM ICE MELT POTENTIAL AND ICE THICKNESS ARE SHOWN (THICK LINES)WITH PARAMETER UNCERTAINTIES (THIN LINES) AS DESCRIBED IN THE TEXT. N I (B), DATES OF INITIAL FREEZE-UP, ICE MELT, AND ICE-OUT ARE SHOWN (THICK LINES) WITH PARAMETER UNCERTAINTIES (THIN LINES) AS DESCRIBED IN THE TEXT. IN (C), THE MODEL OPEN WATER SEASON LENGTH IN SHOWN, INDICATING THAT THERE IS USUALLY AT LEAST 3 MONTHS OF ICE-FREE WATER IN THE MODERN ENVIRONMENT.

MODEL OUTPUT FOR SHIFTING THE MEANNNR AIR TEMPERATURE − 9 TO +5◦ IN (A), MAXIMUM ICE C. MELT POTENTIAL, ICE THICKNESS, AND MULTIYEAR ICE THICKNESS ARE SHOWN (THICK LINES)WITH PARAMETER UNCERTAINTIES (THIN LINES) AS DESCRIBED IN THE TEXT. AFTER A 3. 5◦COOLING, ICE DOES NOT COMPLETELY MELT BEFORE FREEZE-UP BEGINS. IN TERMS OF CREATING ANOXIC CONDITIONS, LIKELY ANOTHER 1– 2◦ COOLING IS REQUIRED TO LEAVE C ICE THICK ENOUGH TO PREVENT WATER– ATMOSPHERE OXYGEN EXCHANGE. IN (B), DATES OF INITIAL FREEZE-UP, ICE MELT, AND ICE-OUT ARE SHOWN (THICK LINES) WITH PARAMETER UNCERTAINTIES (THIN LINES) AS DESCRIBED IN THE TEXT. (C), THE IN UNIFORMLY FROM MODEL OPEN WATER SEASON LENGTH IN SHOWN, WITH THE VALUE RAPIDLY DROPPING OFF TOWARDS ZERO AFTER 3◦ COOLING COMPARED TO MODERN C . TEMPERATURES