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bluewave

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  1. New record sea ice minimums seem to take longer to achieve than most people expect. I can remember the articles calling for an ice free Arctic by 2013 after the record low set in 2007. That record held on for 5 more seasons... longer than it was thought at the time. And after the record was finally broken in 2012, it is still holding on 4 years later despite renewed calls by some for an ice free Arctic by 2015 or 2016. So it will be interesting to see how long it actually takes to get to 1 million sq km or lower on NSIDC. Then the discussion would probably go to how long to zero. That may take a while due to compaction of the remaining sea ice up against the Canadian Archipelago and Greenland.
  2. It's as extreme a pattern reversal that you are going to see from the winter and spring record warmth to cooler summer. That PV was so strong that the Pacific sector North of Alaska to near Siberia was actually colder than 2013 was.
  3. It took the strongest summer Arctic polar vortex since 1996 for the slowest June into late August melt season since 2007 on NSIDC. The polar vortex was actually stronger than we saw in 2013.
  4. This is officially the slowest melt season from June 21st to August 21st on NSIDC going back to 2007. The only reason we are challenging 2nd or 3rd place is due to the record warmth and dipole pattern from the winter into spring. The 2012 record low will last at least 5 years just like the 2007 record low did. NSIDC 6/1-8/21 loss since 2007 2016...6005 2015...6328 2014...6369 2013...6599 2012...7944 2011...6735 2010...6247 2009...6451 2008...6585 2007...7156
  5. The 2012 record is safe no matter how much of an impact this storm has due to the reversal of the pattern in June. We would have had a good shot at at least rivaling the 2012 finish had that dipole persisted into June or July. https://nsidc.org/arcticseaicenews/ While there are still three to four weeks to go in the melt season, a new record low this September is highly unlikely. A simple projection method developed by Walt Meier at the NASA Goddard Space Flight Center uses daily ice loss rates from previous years to estimate possible trajectories of ice extent through the rest of the melt season. This approach yields a range of minimum values based on how sea ice loss progressed in previous years. By selecting from an average of multiple years, or using loss rates from a specific previous year, the method yields an estimate of the likely range of the minimum sea ice extent. As of August 14, using daily ice loss rates based on the 2006 to 2015 average yields an average projected 2016 minimum extent of 4.33 million square kilometers (1.67 million square miles). Using the slowest (recent) August to September decline, which occurred in 2006, yields a 2016 minimum of 4.76 million square kilometers (1.84 million square miles). Using the fastest rate of decline, from 2012, yields a 2016 minimum extent of 4.06 million square kilometers (1.57 million square miles). These two years bracket a reasonable range of expected 2016 minima. It is possible that this year will have decline rates that fall outside the range of previous years. However, this approach indicates that it is very unlikely that 2016 will have a minimum below 2012’s value of 3.39 million square kilometers (1.31 million square miles). A projection from August 1 was submitted to the Sea Ice Outlook.
  6. Interesting that the summer 500 mb pattern went to the CCSM4 long range forecast twice since 2013. Here's the presentation that offers theories why this may be the case: https://ams.confex.com/ams/94Annual/webprogram/Paper235210.html
  7. Slowest loss of sea ice on NSIDC going back to 2007 from June 1st to August 9th. This has to be the most dramatic reversal from a record warm winter and spring dipole pattern to summer polar vortex pattern on record. The summer dipole pattern that dominated the 2007-2012 era has been replaced by more of a polar vortex pattern since then with the exception of last July. We really need that type of a pattern to beat 2012 and make a run on the first ice free minimum. NSIDC sea ice losses from June 1st to August 9th since 2007: 2016...5137 2015...5442 2014...5538 2013...5629 2012...6914 2011...5921 2010...5660 2009...5645 2008...5708 2007...6614
  8. I compiled all the Newark summer temperature data going back to 2010. The 90/95/100 stats are for the warm season and the departures are JJA. Year....90...95...100...JJA 2010...54...21...4.....+3.9 2011...31...16...4.....+3.2 2012...33...17...3.....+1.7 2013...25...10...2.....+1.1 2014...15....2....0.....-0.4 2015...35....8....0.....+1.4
  9. Interesting new study out on Greenland melt. http://jasonbox.net/more-greenland-melt-under-cloudy-conditions/ Our new study reveals that under warm and wet conditions, atmospheric heat can melt the lower 1/3 of the Greenland ice sheet elevations more than under sunny conditions. This was especially so during the 2012 heat wave when a record warm North America loaded the air with heat and moisture that drifted to Greenland. We recorded the largest ever observed daily and annual surface melt rates on Greenland under PROMICE. The 8-11 July, 2012 heat wave produced 0.9 m (3 ft) of ice melt for a yearly total of 8.5 m (28 ft), actually 9% less than the 2010 annual value of 9.2 m (30 ft). The peak daily melt rate was 0.28 m (11 inches) occurred on 11 July. To capture such high melt rates, we use a 12.4 m (40 ft) long ruler. A persistent air flow that drove air up and over west Greenland prevailed for 6 summers (2007 to 2012), parts of 2015, and in other years. This is the same kind of “atmospheric river” that can replenish California’s moisture deficit and cause flooding. In the case of Greenland, if it’s summer and air temperatures are high enough, there will be no snow, just rain and atmospheric heat delivered to the ice surface can do untold damage to the surface. The study decomposes the ice melt energy into contributions. Together, atmospheric heat and condensation delivered more energy to the lower elevations of the ice sheet than absorbed sunlight during pulses in July and August 2012. It’s counterintuitive that under cloudy conditions there can be more melting, especially because the surface is so dark in this lower 1/3 of the ice sheet elevations. It goes to show that the ice sheet melt does not get a break just because the sun is blocked. Climate models under-represent this effect, by our estimate by a factor of two, and with the frequency of warmer air masses driven over Greenland expected to increase with climate change (Collins et al., 2013), the impact of atmospheric heat and condensation will probably bring Greenland ice melt loss faster than forecast.
  10. http://polarportal.dk/en/nyheder/arkiv/nyheder/usaedvanlig-tidlig-afsmeltning-i-groenland/ Unusually Early Greenland Melt By Ruth Mottram, DMI April 12th 2016 An early melt event over the Greenland ice sheet occurred this week, smashing by a month the previous records of more than 10% of the ice sheet melting. Based on observation-initialized weather model runs by DMI, almost 12% of the Greenland ice sheet had more than 1mm of melt on Monday 11th April, following an early start to melting the previous day. Scientists at DMI were at first incredulous due to the early date. “We had to check that our models were still working properly” said Peter Langen, a climate scientist at DMI. “Fortunately we could see from the PROMICE.dk stations on the ice sheet that it had been well above melting, even above 10 °C. This helped to explain the results”. The former top 3 earliest dates for a melt area larger than 10% were previously all in May (5th May 2010, 8th May 1990, 8th May 2006).
  11. 1985-2014 annual 30 year average number of 90 degrees per site: EWR...27 NYC....17 LGA....19 JFK.....10
  12. You can also see peaks in the temp extremes if you choose that option.
  13. You get a strong signal both from temperature and precip extremes which is stronger in some regions than others.
  14. Here's the update on 90 degree days going back to 1984: 90 degree days Year..EWR....NYC....LGA.....JFK 84...22...10...9...13 85...11....9....8....5 86...22...11...9...8 87...37...22...19..11 88...43...32...26...14 89...27...16...17...9 90...26...12...10...6 91...41...39...26...13 92...22.....9...9......6 93...49...39...26...13 94...39...19...22...7 95...33...29...23...15 96....8.....3.....6....4 97...20...12...17...10 98...21.....8....11....5 99...33...27...26....14 00...16....7.....12.....6 01...22...15...17.....8 02...41...32....35...21 03...20....8...17.....12 04...13...2.....7.......1 05...37...23...30.....17 06...26...8....22......12 07...21..10...23.......7 08...22...12...19......9 09...14....7.....8.......6 10...54....37...48.....32 11...31...20...19.....13 12...33...19....28....16 13...25....17....21....9 14...15....8......6.....2
  15. http://www.nws.noaa.gov/oh/hdsc/aep_storm_analysis/11_Islip_2014.pdf Exceedance Probability Analysis for the Islip, NY Rainfall Event, 13 August 2014 Hydrometeorological Design Studies Center National Weather Service National Oceanic and Atmospheric Administration 1325 East­West Highway, Silver Spring, MD 20910 E­mail: [email protected] Updated: 22 August 2014 The Hydrometeorological Design Studies Center (HDSC) analyzed annual exceedance probabilities (AEPs) for the Islip, NY rainfall event that occurred on 13 August 2014. AEP is probability of exceeding a given amount of rainfall at least once in any given year at a given location. It is an indicator of the rarity of rainfall amounts and is used as the basis of hydrologic design. The Islip event delivered rainfall amounts that exceeded 11 inches in 3 hours in some locations, causing extreme flash flooding. The rarity of this event is illustrated in two figures below. Figure 1 shows how the maximum observed rainfall amounts compared to corresponding rainfall frequency estimates for AEPs from 1/2 (50%) to 1/1000 (0.1%) for durations from 30 minutes to 72 hours for a rain gauge in the Islip area ­ KISP, MacArthur Airport (40.7939°N, 73.1017°W, 98 ft elevation). The KISP gauge is part of the Automated Surface Observing System (ASOS). The AEPs are preliminary estimates from unpublished NOAA Atlas 14, Volume 10, Version 1 and may differ from final estimates, which will be released in 2015. The upper bound of the 90% confidence interval for 1/1000 AEP is also shown in the figure to illustrate uncertainty associated with the calculation of AEPs, which increase as the AEP becomes smaller. As can be seen from Figure 1, probabilities are less than 1/1000 for durations between 45­min and 24­hour. Both 2­hour and 3­hour amounts exceed the upper bound of the 90% confidence interval of corresponding 1/1000 estimates.
  16. The updated HADGEM projection will be out soon and it will be good to see it since since the new model shows a slower rate of increase with the -PDO. It's also interesting to see how the November 2012 run captured the cooling of the NW Atlantic relative to recent years with the associated more +AO/+NAO. http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/long-range/decadal-fc
  17. My guess is that as the -PDO era continues, those older forecasts will be dropped in favor of the slower 21st Century warming shown in the recent study by Meehl of about +1.4C of warming by 2100. http://www.scienceda...10918144941.htm To track where the heat was going, Meehl and colleagues used a powerful software tool known as the Community Climate System Model, which was developed by scientists at NCAR and the Department of Energy with colleagues at other organizations. Using the model's ability to portray complex interactions between the atmosphere, land, oceans, and sea ice, they performed five simulations of global temperatures. The simulations, which were based on projections of future greenhouse gas emissions from human activities, indicated that temperatures would rise by several degrees during this century. But each simulation also showed periods in which temperatures would stabilize for about a decade before climbing again. For example, one simulation showed the global average rising by about 2.5 degrees Fahrenheit (1.4 degrees Celsius) between 2000 and 2100, but with two decade-long hiatus periods during the century.
  18. It will probably be a problem that invites more study in the future to try and solve. From a National Science Foundation article on April 15th, 2010: “The heat will come back to haunt us sooner or later,” says NCAR scientist Kevin Trenberth, the lead author. “The reprieve we’ve had from warming temperatures in the last few years will not continue. It is critical to track the build-up of energy in our climate system so we can understand what is happening and predict our future climate.” If the heat is well mixed in the deep ocean below 700 m, exactly how could that heat return to the surface? The second law of thermodynamics suggests that a well mixed heat reservoir in the deep ocean would actually be very inefficient at returning heat to the surface. We need to understand how the ocean exchanges heat vertically, between the upper ocean and deep ocean, and whether mixing in the deep ocean is more efficient than currently thought. Until we understand this, we won’t know to what extent this heat will remain sequestered in the deep ocean. http://judithcurry.com/2013/06/18/ocean-heat-content-discussion-thread/
  19. Not if the deeps ocean heat faster than the surface during -PDO intervals like we are in now.
  20. Not necessarily. Other studies show sensitivity possibly being lower with greater ocean heat uptake. But it will take a long time to know which set of studies are correct. http://link.springer.com/article/10.1007/s00382-013-1770-4 Observational estimate of climate sensitivity from changes in the rate of ocean heat uptake and comparison to CMIP5 models Abstract Climate sensitivity is estimated based on 0–2,000 m ocean heat content and surface temperature observations from the second half of the 20th century and first decade of the 21st century, using a simple energy balance model and the change in the rate of ocean heat uptake to determine the radiative restoration strength over this time period. The relationship between this 30–50 year radiative restoration strength and longer term effective sensitivity is investigated using an ensemble of 32 model configurations from the Coupled Model Intercomparison Project phase 5 (CMIP5), suggesting a strong correlation between the two. The mean radiative restoration strength over this period for the CMIP5 members examined is 1.16 Wm−2K−1, compared to 2.05 Wm−2K−1from the observations. This suggests that temperature in these CMIP5 models may be too sensitive to perturbations in radiative forcing, although this depends on the actual magnitude of the anthropogenic aerosol forcing in the modern period. The potential change in the radiative restoration strength over longer timescales is also considered, resulting in a likely (67 %) range of 1.5–2.9 K for equilibrium climate sensitivity, and a 90 % confidence interval of 1.2–5.1 K.
  21. http://www.ldeo.columbia.edu/news-events/global-heating-hiding-out-oceans A recent slowdown in global warming has led some skeptics to renew their claims that industrial carbon emissions are not causing a century-long rise in Earth’s surface temperatures. But rather than letting humans off the hook, a new study in the leading journal Science adds support to the idea that the oceans are taking up some of the excess heat, at least for the moment. In a reconstruction of Pacific Ocean temperatures in the last 10,000 years, researchers have found that its middle depths have warmed 15 times faster in the last 60 years than they did during apparent natural warming cycles in the previous 10,000. “We’re experimenting by putting all this heat in the ocean without quite knowing how it’s going to come back out and affect climate,” said study coauthor Braddock Linsley, a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory. “It’s not so much the magnitude of the change, but the rate of change.”
  22. That's a statement from one the scientists that wrote the paper in the comments section. Pacific Ocean Heat Content During the Past 10,000 Years Yair Rosenthal1,*, Braddock K. Linsley2, Delia W. Oppo3 +Author Affiliations 1Institute for Marine and Coastal Sciences and Department of Earth and Planetary Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA. 2Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA. 3Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. ↵*Corresponding author. E-mail: [email protected] ABSTRACT EDITOR'S SUMMARY Observed increases in ocean heat content (OHC) and temperature are robust indicators of global warming during the past several decades. We used high-resolution proxy records from sediment cores to extend these observations in the Pacific 10,000 years beyond the instrumental record. We show that water masses linked to North Pacific and Antarctic intermediate waters were warmer by 2.1 ± 0.4°C and 1.5 ± 0.4°C, respectively, during the middle Holocene Thermal Maximum than over the past century. Both water masses were ~0.9°C warmer during the Medieval Warm period than during the Little Ice Age and ~0.65° warmer than in recent decades. Although documented changes in global surface temperatures during the Holocene and Common era are relatively small, the concomitant changes in OHC are large.
  23. It may be that the oceans can absorb more heat that we thought before. http://judithcurry.com/2013/11/01/pacific-ocean-heat-content-for-the-past-10000-years/ Yair Rosenthal: The fact that 300 years ago the ocean heat content was so low, I use the word capacitor in the paper. We can charge it a lot…. Maybe the ocean is taking the heat more and won’t exhale it as much. That’s the challenge I have for the modelers.
  24. A new study just out addresses how the PDO can impact global temperatures on a decadal timescale. http://www.climatecentral.org/news/why-the-globe-hasnt-warmed-much-for-the-past-decade-15788 The natural variation in this case appears to be changes in wind patterns associated with the Pacific Decadal Oscillation, or PDO, a gradual see-sawing of ocean surface temperatures and wind patterns that goes through warm and cold phases lasting several decades. (The more familiar El Nino/La Nina oscillation, by contrast, see-saws every few years). According to Trenberth and his colleagues, deep ocean temperatures began to rise significantly starting in about 2000, at about the same time as trade winds in the Pacific were changing in strength, in turn affecting ocean currents, all very plausibly as a result of a shift in the PDO. http://www.skepticalscience.com/new-research-confirms-global-warming-has-accelerated.html This study builds on another paper published in 2011. http://www.cgd.ucar.edu/cas/Staff/Fasullo/my_pubs/Meehl2011etalNCC.pdf There have been decades, such as 2000–2009, when the observed globally averaged surface-temperature time series shows little positive or even slightly negative trend1 (a hiatus period). However, the observed energy imbalance at the top-of-atmosphere for this recent decade indicates that a net energy flux into the climate system of about 1 W m−2 7 (refs 2,3) should be producing warming somewhere in the system4,5 . Here we analyse twenty-first-century climate-model simulations that maintain a consistent radiative imbalance at the top-of-atmosphere of about 1 W m−2 as observed for the 11 past decade. Eight decades with a slightly negative global mean surface-temperature trend show that the ocean above 300 m takes up significantly less heat whereas the ocean below 300 m takes up significantly more compared with non-hiatus decades. The model provides a plausible depiction of processes in the climate system causing the hiatus periods, and indicates that a hiatus period is a relatively common climate phenomenon and may be linked to La Niña-like conditions. The time series of globally averaged surface temperature from all five climate-model simulations show some decades with little or no positive trend (Fig. 1a), as has occurred in observations (Supplementary Fig. S1 top). Running ten year linear trends of globally averaged surface temperature from the five model ensemble members reveal hiatus periods (Fig. 1a) comparable to observations (Supplementary Fig. S1 middle). Using the first ensemble member as an example, the overall warming averaged over the century is about +0.15 ◦ C per decade. However, the decades centred around 2020, 2054, 2065, 2070, and several decades late in the century show either near zero or slightly negative trends in that ensemble member. We choose two ten year periods in this ensemble member when the globally averaged surface temperature is negative, that is, less than −0.10 ◦ C over the decade (Fig. 1a), and six similar periods that meet the same criterion from the other four ensemble members, to form an eight-member composite of hiatus periods. http://www.sciencedaily.com/releases/2011/09/110918144941.htm To track where the heat was going, Meehl and colleagues used a powerful software tool known as the Community Climate System Model, which was developed by scientists at NCAR and the Department of Energy with colleagues at other organizations. Using the model's ability to portray complex interactions between the atmosphere, land, oceans, and sea ice, they performed five simulations of global temperatures. The simulations, which were based on projections of future greenhouse gas emissions from human activities, indicated that temperatures would rise by several degrees during this century. But each simulation also showed periods in which temperatures would stabilize for about a decade before climbing again. For example, one simulation showed the global average rising by about 2.5 degrees Fahrenheit (1.4 degrees Celsius) between 2000 and 2100, but with two decade-long hiatus periods during the century. Metoffice decadal forecast using a similar theme: http://www.metoffice.gov.uk/news/releases/archive/2013/decadal-forecasts http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/long-range/decadal-fc http://www.metoffice.gov.uk/research/news/decadal-forecasting
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