2001

1. [Barnett et al. 2001]
   ABSTRACT: Large-scale increases in the heat content of the worldÕs oceans have been observed to occur over the last 45 years. The horizontal and temporal character of these changes has been closely replicated by the state-of-the-art Parallel Climate Model (PCM) forced by observed and estimated anthropogenic gases. Application of optimal detection methodology shows that the model-produced signals are indistinguishable from the observations at the 0.05 confidence level. Further, the chances of either the anthropogenic or observed signals being produced by the PCM as a result of natural, internal forcing alone are less than 5 %. This suggests that the observed ocean heat-content changes are consistent with those expected from anthropogenic forcing, which broadens the basis for claims that an anthropogenic signal has been detected in the global climate system. Additionally, the requirement that modeled ocean heat uptakes match observations puts a strong, new constraint on anthropogenically forced climate models. It is unknown if the current generation of climate models, other than the PCM, meet this constraint.
   Climate change detection, attribution, warming oceans.

2. [Beltrami 2001a]
   Analysis of recrods of air and soil temperature at Pomquet. Air-soil differences may be related to incoming solar radiation. Soil tracks air temperatures in spring and autumn. Snow cover and winter freezing can have an effect on the coupling. Phase-space plots are an interesting representation of thermal regime with depth. Subsurace temperatures can be obtained via the forward model (appropriate for shallow layer and estimation of temperature variation) and finite difference model. Finite difference model can be further used to estimate thermal diffusivity with depth at several layers.
   Climate reconstructions, global warming evidence, borehole climatoloty.

3. [Beltrami 2001b]
   Stablishes method to estimate GSFHistories from borehole profiles. From temperature profile calculates flux profile and from there inverts it. Good example with a deep (600 m) borehole which yields an inversion of 1000 yr showing something like a LIA.
   Climate reconstructions, global warming evidence, borehole climatology, heat flux.

4. [Beltrami 2001c]
   Extension of [Beltrami 2001c].
   Climate reconstructions, global warming evidence, borehole climatology, heat flux.

5. [Beltrami and Harris 2001]
   Foreword for Blobal and Planetary Change volume. Wrap up of 10 years as introduction. Brief remark on historical origin and scheme of the three general approaches to inversion (ramp-step models, staircase models and functional space inversion). Brief description of borehole approach
   Climate reconstructions, global warming evidence, borehole climatology.

6. [Bond et al. 2001]
   ABSTRACT: Surface winds and surface ocean hydrography in the subpolar North Atlantic appear to have been inßuenced by variations in solar output through the entire Holocene. The evidence comes from a close correlation between inferred changes in production rates of the cosmogenic nuclides carbon-14 and beryllium-10 and centennial to millennial time scale changes in proxies of drift ice measured in deep-sea sediment cores. A solar forcing mechanism therefore may underlie at least the Holocene segment of the North AtlanticÕs 1500-year cycle. The surface hydrographic changes may have affected production of North Atlantic Deep Water, potentially providing an additional mechanism for amplifying the solar signals and transmitting them globally.
   Climate change, holocene, solar variability

7. [Boville et al. 2001]
   Improvements to the NCAR Climate System Model, CSM-1, primarily for transient climate forcing simulations, are discussed. The impact of the individual changes is assessed through atmosphere?land or ocean?ice exper- iments, and through short coupled simulations. A 270-yr control simulation has been performed using the model with all of the changes, de?ned as CSM-1.3. Trace gas concentrations appropriate for 1870 were used and the model produced a stable surface climate with less deep ocean drift than CSM-1. Changing the aerodynamic roughness length of sea ice to a value appropriate for ?rst year ice reduced the deep ocean salinity trend by a factor of 100 and error in the transport by the Antarctic circumpolar current by 50% (60 10 6 m 3 s 1 ). Three new features were added to the Community Climate Model, version 3 (CCM3), which is the atmospheric component of CSM-1. These additions were N 2O, CH 4 , CFC11, and CFC12 as prognostic tracers and the oxidation of CH 4 to form water vapor ; a prognostic cloud water formulation; and direct radiative effects of sulfate aerosols from a sulfate chemistry model (either online or using previously calculated three- dimensional aerosol loadings). Although these features represent substantial changes to the CCM3 formulation, allowing greatly improved ?exibility for climate change experiments, they have relatively modest impact on the control simulation.
   Climate model, last millennium, NCAR

8. [Bradley 2001]
   Reaction to editorial of D. Kennedy (An unfortunate Uturn on carbon' defending no apreciable warming trend in the passt 60 years. Bradley provides citations of different evidence of global warming.
   Climate reconstructions, global warming evidence.

9. [Bradley et al. 2001]
   Reaction to [Broecker 2001] pointing that evidence of a climate optimum in medieval times is regional. Defend the need for a network of proxies.
   Climate reconstructions, last millenium, borehole, tree ring.

10. [Briffa et al. 2001]
    Reconstructions of northern extratropical summer temperatures for nine subcontinental scale regions and a composite series representing quasi NH temperature change over the past 600 years.
    Tree ring reconstructions, last millennium.

11. [Broecker 2001] Provides/recalls evidence of medieval warming in specific regions critizicing that the [Mann et al. 1999] reconstruction does not show a clear medieval warming. Critisizes the use of tree ring data and corals to reproduce long term climate variability and favours glacial records and boreholes. Presents an hypothesis of the apparent 1500 yr oscilation in the Holocene relating it to salt variations in the ocean and conveyor belt variability and convecttion in the north atlantic.
    Holocene variability, medieval optimum.

12. [Members 2001] To evaluate the spatial variability ofArctic climate change during the present interglacial,CAPE Project Members compiled well-dated terrestrial,marine,and ice-core paleoenvironmental records spanning the past 10 -12 thousand years (ka).Six tundra biomes ofincreasing summer temperature requirements were de " based on regionally coherent pollen assemblages.Using a rule-based approach,pollen spectra were converted to tundra,forest/tundra,or forest biomes ranked by their average growing season requirements.Marine sea-surface reconstructions were based on proxy data following a similar rule-based approach.From these data-based reconstructions,departures in summer temperatures from modern normals were calculated in 1 ka time slices through the Holocene.To test predictive models,data-based summer temperature reconstructions were compared with general circulation model (GCM)simulations for 10 ka and 6 ka ago.Paleodata and model results both show that warming occurred earlier across Beringia and Asia relative to lands adjacent to the North Atlantic,and that Late Holocene cooling was most apparent in the North Atlantic region.However,the GCM over-predicts the magnitude ofMid-Holocene warming over northern Asia and underestimates the intensi ofthe North Atlantic drif in the early Holocene.Strong spatial variability in environmental response during the Holocene,despite symmetric (insolation)forcing,suggests that any future changes,whether caused by anthropogenic or natural factors,are unlikely to result in a uniform change across the Arctic,adding additional complexity to forecasts of global impacts. 2001 Elsevier Science Ltd.All rights reserved.
    Holocene climate change, Arctic variability, models, proxy.

13. [Correia and Safanda 2001] Analysis of GST variations in a single borehole using the functional space inversion method near Evora. The inverted profile suggest a change of about 1 degree since the end of the 19th century consistent with observations at Lisbon. Estimation of preobservational mean.
    Borehole temperatures, inversion methods, Portugal

14. [Diaz et al. 2001] ABSTRACT There is great interest in the climatic variability of Baja California and the Sea of Cortes, but long-term information is limited because instrumental climate records begin in the 1940s or 1960s. The first tree-ring chronology of Pinus lagunae was developed from the southern part of the Baja California Peninsula and the chronology is used to reconstruct the history of precipitation variations. A September July precipitation reconstruction is developed for the period AD 1862 1996 (Rolsi 0.71, p 0.0001, nolsi 56, cross-validationolsi 0.68). This reconstruction is used to assess precipitation variability over the past two centuries, including the relationship with ENSO events. The reconstructed precipitation series indicates a long drought period from 1939 to 1958. It also shows that 1983, one of the strongest El NinÜ o events of the 20th century, is the wettest year. El NinÜ o events during the 20th century are associated with above-normal precipitation, whereas La NinÜ a events are characterized by below-normal precipitation. Four of the most extreme wet years occurred in association with these warm events (1905, 1912, 1919 and 1983). Seventy-one percent of La NinÜ a events are characterized by below-normal precipitation. Sixty-two percent of El NinÜ o events are characterized by above-normal precipitation. Tree-ring growth of P. lagunae is most strongly correlated with winter precipitation in Sonora, Sinaloa and southern Baja California Sur. Precipitation data from meteorological stations in northern Baja California do not correlate well with the tree-ring chronology because this zone has a Mediterranean climate, which differs from the rest of northwest Mexico. Copyright © 2001 Royal Meteorological Society. KEY WORDS: Baja California Sur, Mexico; dendroclimatology; ENSO-precipitation; Pinus lagunae; Sierra de La Laguna DOI: 10.1002ao
    Paleoclimate reconstructions, tree-ring, enso, hidrology

15. [Golovanova et al. 2001] Abstract:Thirty borehole temperature depth profiles in the central and southern Urals, Russia were scrutinized for evidence of ground surface temperature histories. We explored two inversion schemes: a simple ramp inversion in which solutions are parameterized in terms of an onset time and magnitude of change and a more sophisticated functional space inverse algorithm in which the functional form of the solution is left unspecified. To enhance and potentially identify latitudinal differences in the ground surface temperature signal, we subdivided the data into three groups based on geographic proximity and simultaneously inverted the borehole temperature depth logs. The simultaneous inversions highlighted 13 temperature depth logs that could not both fit a common ground surface temperature history and a priori models within reasonable bounds. Our results confirm that this is an effective way to reduce site-specific noise from an ensemble of boreholes. Each inversion scheme gives comparable results indicating locally variable warming on the order of 1olsi C starting between 1800 and 1900 AD. Similarly surface air temperature records from 12 nearby meteorological stations exhibit locally variable warming also on the order of 1olsi C of warming during the 20th century. To explore the degree to which borehole temperatures and surface air temperature SAT time series are responding to the same signal, we average the SAT data into the same three groups and used these averages as a forcing function at the Earth s surface to generate synthetic transient.temperature profiles. Root mean square RMS misfits between these synthetic temperature profiles and averaged temperature depth profiles are low, suggesting that first-order curvature in borehole temperatures and variations in SAT records are correlated.
    Borehole temperatures, inversion methods, Urals

16. [Ganopolski and Rahmstorf 2001] Abrupt changes in climate, termed Dansgaard±Oeschger and Heinrich events, have punctuated the last glacial period (,100± 10 kyr ago) but not the Holocene (the past 10 kyr). Here we use an intermediate-complexity climate model to investigate the stability of glacial climate, and we ®nd that only one mode of Atlantic Ocean circulation is stable: a cold mode with deep water formation in the Atlantic Ocean south of Iceland. However, a `warm' circulation mode similar to the present-day Atlantic Ocean is only marginally unstable, and temporary transitions to this warm mode can easily be triggered. This leads to abrupt warm events in the model which share many characteristics of the observed Dansgaard±Oeschger events. For a large freshwater input (such as a large release of icebergs), the model's deep water formation is temporarily switched off, causing no strong cooling in Greenland but warming in Antarctica, as is observed for Heinrich events. Our stability analysis provides an explanation why glacial climate is much more variable than Holocene climate.
    Paleoclimate reconstructions, tree-ring, enso, hidrology

17. [González-Rouco et al. 2001]
    A quality control process involving outliers processing, homogenization, and interpolation has been applied to 95 monthly precipitation series in the Iberian Peninsula, southern France, and northern Africa during the period 1899 1989. A detailed description of the procedure results is provided and the impact of adjustments on trend estimation is discussed. Outliers have been censored by trimming extreme values. Homogeneity adjustments have been developed by applying the Standard Normal Homogeneity Test in combination with an objective methodology to select ref-erence series. The spatial distribution of outliers indicates that they are due to climate variability rather than measurement errors. After carrying out the homogeneity procedure, 40% of the series were found to be homogeneous, 49.5% became homogeneous after one adjustment, and 9.5% after two adjustments. About 30% of the inhomogeneities could be traced to information in the scarce history files. It is shown that these data present severe homogeneity problems and that applying outliers and homogeneity adjustments greatly changes the patterns of trends for this area.
    Quality control, homogeneization, spanish precipitation

18. [Giorgi et al. 2001]
    State of the art in downscaling. Chapter of [J. et al. 2001]
    Downscaling methods.

19. [Hasanean 2001]
    ABSTRACT: Changes in surface air temperature during the last century are widely discussed among researchers in the field of climatic change. Using various techniques, we investigate trends and periodicity of surface air temperature series from eight meteorological stations in the Eastern Mediterranean. For the analysis, we use the Mann-Kendall rank test, low- pass filtering, autocorrelation spectral analysis and maximum entropy spectral analysis. The latter two tests are compared. The study is based on series over one hundred years in length for four stations, and over fifty years in length for the other four. Increasing and decreasing surface temperature trends were found. These trends, however, are only significant for Malta, Jerusalem, and Tripoli at the 99% confidence level (positive trend) and for Amman at the 95% cofidence level (negative trend). We also found inter-decadal variations in surface air temperature, including a fairly regular quasi 20- year oscillation, although its amplitude varied between different cycles. A period of warming began around 1910 at all stations. During the 1970s, the annual mean tem- perature series exhibit warming, but this warming was not uniform, continuous or of the same order at all the stations. The results of the Autocorrelation Spectral Analysis and the Maximum Entropy Spectral Analysis are similar, pointing to the reliability of the results. The quasi-biennial oscillation (QBO) exists at all stations during both increasing and decreasing trends. Similarly, a broad maximum from 3+-8 years (related to El Nin Ä o) is found at Malta, Athens, Jerusalem, Beirut, and Latakia. An inverse relationship between El Nin Ä o and the North Atlantic Oscillation with surface air temperature over the Eastern Mediterranean is found at a highly significant confidence level.
    Eastern Mediterranean, temperature, Mann-Kendal, ENSO, QBO, NAO

20. [Harris and Chapman 2001]
    Generate NH borehole temparture profile and reconstruction with bayesian method with a priori hypothesis. Compare results with reconstructions. The reconstructed temperature profile is in good correspondence with SAT.
    Paleoclimate reconstructions, multi proxy, borehole temperature, sat.

21. [Hoerling et al. 2001]
    State of tropical Indo-Pacific region force variability in NAO. GCM ensembles with historical SSTs in the Indo Pacific region and climatology in the rest force historical NAO. Tropical Atlantic NAO reproduce the same signal but weaker. Changes since 1950 can be explained on the basis of this conection. No physical explanation for the links so far. It is not unreasonable to claim that the North Atlantic European climate change forced by the imposed solar slow warming of tropical SSTs constitutes an anthropogenic signal that has just begun to emerge during the last half-century.
    Indo pacific region, climate variability, climate change, NAO, ENSO.

22. [J. et al. 2001]
    Ref to IPCC 2001
    Climate change et al.

23. [Jones et al. 2001]
    Description of sources for paleoclimate reconstructions. Temperatures at the end of the 20th century probably the warmest during the last 1000 years. Discussion of SOI and NAO reconstructions. Need for more proxies.
    Last Millenium. NH temperatures. NAO. SOI. Reconstructions

24. [Kennedy and O'Hagan 2001]
    They consider prediction and uncertainty analysis for systems which are aproximated using complex mathematical models. Good descripiton of different errors and uncertainties inherent to various stages of models use. Cascade of errors. Uncertainty estimation within aleatory and epistemic contexts.
    Climate change uncertainties, calibration, computer experiments, deterministic models, gaussian process, uncertainty analysis.

25. [Kushner et al. 2001]
    Response of SH circulation to greenhouse gases forcing. Interesting to understand dynamical response. Interesting discussion on the effects of stratsopheric forcing. AAO encrease
    AAO, Southern hemisphere, climate change, circulation.
    

26. [Levitus et al. 2001]
    ABSTRACT: We compared the temporal variability of the heat content of the world ocean, of the global atmosphere, and of components of EarthÕs cryosphere during the latter half of the 20th century. Each component has increased its heat content (the atmosphere and the ocean) or exhibited melting (the cryosphere). The estimated increase of observed global ocean heat content (over the depth range from 0 to 3000 meters) between the 1950s and 1990s is at least one order of magnitude larger than the increase in heat content of any other component. Simulation results using an atmosphere-ocean general circulation model that includes estimates of the radiative effects of observed temporal variations in greenhouse gases, sulfate aerosols, solar irradiance, and volcanic aerosols over the past century agree with our observation-based estimate of the increase in ocean heat content. The results we present suggest that the observed increase in ocean heat content may largely be due to the increase of anthropogenic gases in Earths atmosphere.
    Climate change, warming, ocean warming, detection, attribution.
    

27. [Lockwood and Owens 2011]
    Svalgaard and Cliver (2010) recently reported a consensus between the various reconstructions of the heliospheric field over recent centuries. This is a significant development because, individually, each has uncertainties introduced by instrument calibration drifts, limited numbers of observatories, and the strength of the correlations employed. However, taken collectively, a consistent picture is emerging. We here show that this consensus extends to more data sets and methods than reported by Svalgaard and Cliver, including that used by Lockwood et al. (1999), when their algorithm is used to predict the heliospheric field rather than the open solar flux. One area where there is still some debate relates to the existence and meaning of a floor value to the heliospheric field. From cosmogenic isotope abundances, Steinhilber et al. (2010) have recently deduced that the near Earth IMF at the end of the Maunder minimum was 1.80 ± 0.59 nT which is considerably lower than the revised floor of 4nT proposed by Svalgaard and Cliver. We here combine cosmogenic and geomagnetic reconstructions and modern observations (with allowance for the effect of solar wind speed and structure on the near Earth data) to derive an estimate for the open solar flux of (0.48 ± 0.29) × 1014 Wb at the end of the Maunder minimum. By way of comparison, the largest and smallest annual means recorded by instruments in space between 1965 and 2010 are 5.75 × 1014 Wb and 1.37 × 1014 Wb, respectively, set in 1982 and 2009, and the maximum of the 11 year running means was 4.38 × 1014 Wb in 1986. Hence the average open solar flux during the Maunder minimum is found to have been 11 of its peak value during the recent grand solar maximum.
    Climate change, detection, attribution.
    

28. [Luterbacher et al. 2001]
    ABSTRACT: The Late Maunder Minimum (LMM, 1675 1715) denotes the climax of the Little Ice Age in Europe with marked climate variability. Investigations into interannual and interdecadal differences of atmospheric circulation between the LMM and the period 1961 1990 have been performed and undertaken based upon sea level pressure (SLP) difference maps, empirical ortho-gonal function (EOF) analysis, and objective classification techniques. Since the SLP during the LMM winter was significantly higher in northeastern Europe but below normal over the central and western Mediterranean, more frequent blocking situations were connected with cold air outbreaks towards central and eastern Europe. Springs were cold and characterized by a southward shift of the mid-latitude storm tracks. Summers in western, central Europe and northern Europe were wetter and slightly cooler than they are today due to a weaker Azores high and a more southerly position of the mean polar front axes. Autumns showed a significantly higher pressure over northern Europe and a lower pressure over continental Europe and the Mediterranean, an indication of an advanced change from summer to winter circulation. It is suggested that the pressure patterns during parts of the LMM might be attributed to the combination of external forcing factors (solar irradiance and volcanic activity) and internal oscillations and couplings in the North Atlantic.
    Climate change, detection, attribution.
    

29. [Mitchell et al. 2001]
    Detection and attribution chapter in IPCC01.
    Climate change, detection, attribution.
    

30. [Oreskes and Belitz 2001]
    Model validation in the context of Earth Sciences
    Models, validation, verification.
    

31. [Pastor et al. 2001]
    Use the RAMS (previous version of MM5) model to simulate torretial events of precip in the SE of the Iberian Peninsula. Use several SST as forcing boundary conditions. The effects of SSTs are determinant. Maximum precipitations seems to be related to average sst or to the trayectory and displaced inland
    RAMS, MM5, Mediterranean, torrencial events.
    

32. [Pozo-Vázquez et al. 2001a]
    ENSO impacts on European temperature and over the Ib. Peninsula. ENSO impacts on circulation. Relevant relation in La Nina phases.
    ENSO, temperature, Europe, Iberian Peninsula.

33. [Pozo-Vázquez et al. 2001b]
    Nonlinear influence of NAO on European temperature.
    NAO, temperature, Europe, Iberian Peninsula.

34. [Raible et al. 2001] Non stationarity in NAO regimes in the ECHOg Model
    NAO, echog

35. [Robertson et al. 2001] Volcanic forcing for the last 500 years
    Volcanic forcing

36. [Serban et al. 2001]
    Effects of topography and groundwater flow on the subsurface thermal regime
    Boreholes, climate reconstructiosn

37. [Schulz et al. 2001]
    Abstract Three versions of the single-column European Centre for Medium-Range Weather Forecasts–Hamburg (ECHAM4) climate model are compared that differ either in the technique of the numerical coupling between land surface and atmosphere or the physical parameterization of the land surface processes. The standard ECHAM4 model utilizes a semi-implicit coupling technique between land surface and atmosphere in a way in which energy at the land surface–atmosphere interface is not conserved. This is a major deficiency. Two new model versions were developed: ECHAM4/IMPL and ECHAM4/SECHIBA. They incorporate an implicit coupling technique that conserves energy. ECHAM4 and ECHAM4/IMPL are identical with respect to all physical parameterizations they apply; the only difference is the coupling. In ECHAM4/SECHIBA, the ECHAM land surface scheme was replaced by SECHIBA (Schématisation des Echanges Hydriques à l’Interface entre la Biosphère et l’Atmosphère). The intercomparison of one-dimensional versions of these three models shows that the energy residual term in ECHAM4 is not negligibly small, but it is rather of the order of the physical fluxes. Biases of more than 1300 W m−2 are found due to the coupling technique. These are avoided in ECHAM4/IMPL, which results in a more pronounced diurnal cycle of surface temperature and generally higher temperature maxima during a warming phase. In an offline intercomparison of the three model versions, using an observational atmospheric forcing dataset, an important impact of the coupling technique on the simulated surface energy cycle is found as well. The turbulent heat fluxes in ECHAM4 tend to be underestimated; their rise in the morning and decrease in the afternoon are delayed. Because of the improved coupling, the turbulent heat fluxes of the implicit models are in better agreement with the observations, especially regarding the phases of their diurnal cycles. Differences between ECHAM4/IMPL and ECHAM4/SECHIBA are mainly found for the simulated surface temperature, which gets closer to the observed radiative temperature for the latter model. Furthermore, the diurnal amplitude of the ground heat flux is increased in ECHAM4/SECHIBA in agreement with the observations.
    Land air interactions echam

38. [Shindell et al. 2001]
    Response of GCM to irradiance changes during the late 17th century and late 18th century. Use GCM GISS with detailed representation of stratosphere and mixed ocean layer. The global response is usual (0.3-0.4 C), the regional response is however not so small and occurs through a shift towards the low index state of the NAO.
    Paleoclimate, AO, NAO, solar forcing, GCM, stratosphere, global warming, artic.
    

39. [Slonosky et al. 2001]
    London-Paris index. Used as referenced in [Shindell et al. 2001]. Supports that during LMM the AO shifted to a negative phase.
    Circulation indices, early instrumental obsrevations, climate reconstructions.

40. [Trenberth and Caron 2001]
    Abstract: New estimates of the poleward energy transport based on atmospheric reanalyses from the National Centers for Environmental Prediction National Center for Atmospheric Research (NCEP NCAR) and the European Centre for Medium-Range Weather Forecasts are presented. The analysis focuses on the period from February 1985 to April 1989 when there are reliable top-of-the-atmosphere radiation data from the Earth Radiation Budget Experiment. Annual mean poleward transports of atmospheric energy peak at 5.0 6 0.14 PW at 438N and with similar values near 408S, which is much larger than previous estimates. The standard deviation of annual and zonal mean variability from 1979 to 1998 is mostly less than 0.15 PW (1% 3%). Results are evaluated by computing the implied ocean heat transports, utilizing physical constraints, and comparing them with direct oceanographic estimates and those from successful stable coupled climate models that have been run without artificial flux adjustments for several centuries. Reasonable agreement among ocean transports is obtained with the disparate methods when the results from NCEP NCAR reanalyses based upon residually derived (not modelgenerated) methods are used, and this suggests that improvements have occurred and convergence is to the true values. Atmospheric transports adjusted for spurious subterranean transports over land areas are inferred and show that poleward ocean heat transports are dominant only between 08 and 178N. At 358 latitude, at which the peak total poleward transport in each hemisphere occurs, the atmospheric transport accounts for 78% of the total in the Northern Hemisphere and 92% in the Southern Hemisphere. In general, a much greater portion of the required poleward transport is contributed by the atmosphere than the ocean, as compared with previous estimates.
    Ocean, atmosphere heat transport

41. [Wanner et al. 2001]
    Review of NAO studies
    NAO