[1] We present the Met Office Hadley Centre's sea ice and sea surface temperature (SST) data set, HadISST1, and the nighttime marine air temperature (NMAT) data set, HadMAT1. HadISST1 replaces the global sea ice and sea surface temperature (GISST) data sets and is a unique combination of monthly globally complete fields of SST and sea ice concentration on a 1° latitude-longitude grid from 1871. The companion HadMAT1 runs monthly from 1856 on a 5° latitude-longitude grid and incorporates new corrections for the effect on NMAT of increasing deck (and hence measurement) heights. HadISST1 and HadMAT1 temperatures are reconstructed using a two-stage reduced-space optimal interpolation procedure, followed by superposition of quality-improved gridded observations onto the reconstructions to restore local detail. The sea ice fields are made more homogeneous by compensating satellite microwave-based sea ice concentrations for the impact of surface melt effects on retrievals in the Arctic and for algorithm deficiencies in the Antarctic and by making the historical in situ concentrations consistent with the satellite data. SSTs near sea ice are estimated using statistical relationships between SST and sea ice concentration. HadISST1 compares well with other published analyses, capturing trends in global, hemispheric, and regional SST well, containing SST fields with more uniform variance through time and better month-to-month persistence than those in GISST. HadMAT1 is more consistent with SST and with collocated land surface air temperatures than previous NMAT data sets.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2002JD002670

Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century

A weekly 1° spatial resolution optimum interpolation (OI) sea surface temperature (SST) analysis has been produced at the National Oceanic and Atmospheric Administration (NOAA) using both in situ and satellite data from November 1981 to the present. The weekly product has been available since 1993 and is widely used for weather and climate monitoring and forecasting. Errors in the satellite bias correction and the sea ice to SST conversion algorithm are discussed, and then an improved version of the OI analysis is developed. The changes result in a modest reduction in the satellite bias that leaves small global residual biases of roughly −0.03°C. The major improvement in the analysis occurs at high latitudes due to the new sea ice algorithm where local differences between the old and new analysis can exceed 1°C. Comparisons with other SST products are needed to determine the consistency of the OI. These comparisons show that the differences among products occur on large time- and space scales wit...

An Improved In Situ and Satellite SST Analysis for Climate

Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

/pdf/climate-change-2007-the-physical-science-basis-1x93ttz9jt.pdf

Climate Change 2007: The Physical Science Basis.

With digital equipment becoming increasingly networked, either on wired or wireless networks, for personal and professional use alike, distributed software systems have become a crucial element in information and communications technologies. The study of these systems forms the core of the ARLES' work, which is specifically concerned with defining new system software architectures, based on the use of emerging networking technologies. In this context, we concentrate on the study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence.

반도체 공정 overview

This chapter assesses long-term projections of climate change for the end of the 21st century and beyond, where the forced signal depends on the scenario and is typically larger than the internal variability of the climate system. Changes are expressed with respect to a baseline period of 1986-2005, unless otherwise stated.

Chapter 12 - Long-term climate change: Projections, commitments and irreversibility

A prominent optical phenomenon associated with the physics of the ionosphere

Some intriguing statistical evidence from readily available data suggests that longer-term (>11-year) solar activity cannot be overlooked as a potential cause of an appreciable part of twentieth-century global warming, and might in particular explain the latter's hiatus or even slight reversal between 1940-70. On this basis, global warming is predicted to continue as projected solar activity increases towards and beyond the millennium.

Solar-driven global warming

Concerted observational and modelling programmes are underway to determine thecurrent state and variability of mass balance of the Greenland Ice Sheet, hence helppredict its response to future climatic change. Here we present the results of new meteorologicalmodelling based on ERA-40 reanalysis data from the European Centre forMedium RangeWeather Forecasts (ECMWF). This gives us valuable insights into thepast and present state and variability of the Greenland ice mass and links with climate.Here we show for the first time a validated annual and seasonal surface-mass-balancehistory of the ice sheet for 1957-2003. This is based on a novel monthly melt-waterrunoff model by Janssens Huybrechts (Huybrechts 2002). We show considerable interannualvariability in snow accumulation, runoff and mass balance over the last 45years, with some intriguing recent results. By comparing with long-term temperature,precipitation and accumulation records from the met. stations and ice cores, we discusspossible climatic factors forcing the ice in this period. We also derive sensitivityof the ice sheet to climatic forcing, based on real meteorological observations (ERA-40). The intriguing results include massive snow accumulation over south-east Greenlandduring winter 2002/03, which led to unprecedented thickening in the most recentNASA aircraft surveys. Is this recent thickening signal a sign of more extreme weatherconditions over the Ice Sheet, more storminess and higher accumulation events, dueto global warming?

State and variability of mass balance of Greenland Ice Sheet since 1957, and links with climate

Greenland Ice Sheet surface mass balance 1870 to 2010 based on Twentieth Century Reanalysis, and links with global climate forcing

The iceberg hazard for the Grand Banks area to the east of Newfoundland varies dramatically from one year to the next. In some years no icebergs penetrate south of 48oN, while in others well over 1000 icebergs enter the main shipping lanes between Europe and NE North America. Advance knowledge of this seasonal hazard would have major implications for ship routing, as well as the resources required for maintaining an effective ice hazard service. Here, a Windowed Error Reduction Ratio control system identification approach is used to forecast the severity of the 2018 iceberg season off Newfoundland, in terms of the predicted number of icebergs crossing 48oN, as well as to hindcast iceberg numbers for 2017. The best estimates are for 766±297 icebergs crossing 48oN before the end of September 2017 and 685±207 for 2018. These are both above the recent observed average of 592 icebergs for that date, and substantially so for 2017. Given the bimodal nature of the annual iceberg number, this means that our predictions for both 2017 and 2018 are for a high iceberg season, with a 71% level of confidence. However, it is most likely that the 2018 iceberg numbers will be somewhat less than 1000, while our higher hindcast for 2017 is consistent with the observed level of 1008. Our verification analysis, covering the 20-year period up to 2016, shows our model’s correspondence to the high or low nature of the 48oN iceberg numbers is statistically robust to the 0.05 % level, with a skill level of 80%.

/pdf/forecasting-the-severity-of-the-newfoundland-iceberg-season-29savf16za.pdf

Edward Hanna

Papers

A prominent optical phenomenon associated with the physics of the ionosphere

Solar-driven global warming

State and variability of mass balance of Greenland Ice Sheet since 1957, and links with climate

Greenland Ice Sheet surface mass balance 1870 to 2010 based on Twentieth Century Reanalysis, and links with global climate forcing

Forecasting the severity of the Newfoundland iceberg season using a control systems model