2002

[Beltrami 2002b]
A discussion on the comparison between proxy reconstructions and borehole reconstructions. Nice plot with temperature anoomaly profiles.
Last Millenium. Borehole temeprature reconstructions
[Beltrami 2002a]
Changes in temperature and ground heat flux for the last 500 years. Global average ground temperature and ground flux have increased an average of 0.45K and 18 mWm2 over the last 200 years. The continental surface absorved 7.1 $10^{21}$ J in the last 50 years, similar to Levitus et al. (2001). Interesting comments about eigenvalue cutoff.
Last Millenium. Borehole temeprature and heat flux reconstructions
[Beltrami et al. 2002]
Estimation of heat flux into continental areas from borehole temperature data. First deduce GSTH and estimate GSFH from that. Continental litosphere has gained J in the last 50 years, J in the last 500 years. Supports conclusion of flobal warming of litosphere.
Last Millenium. Borehole temeprature and heat flux reconstructions
[Briffa and Osborn 2002]
Comments on [Esper et al. 2002]. MWP more evident. Better agreement with boreholes.
Last Millenium. NH temperatures. Reconstructions
[Castro-Diez et al. 2002]
Comments on the relationship between NAO and temperatures in southern Europe. Temperature anomaly patterns are sensitive to the structure and position of the NAO. Suggest potential non linear relationship.
NAO, southern Europe, temperature.
[Cook and Esper 2002]
Dont agree with [Mann and Hughes 2002] that the scaling of theri record is flawed. Their record is not reliable under 20 yrs but compares well with other reconsturctions on long term trends. Also dont agree theri results for the MWP were wrong due to the small number of chronologies. They rely on their confidence limits and comparison with other reconstructions. There are significant periods of above average growth during the MWP.
Last Millenium. NH temperatures. Reconstructions
[Cook et al. 2002]
The occurrence of the Medieval Warm Period (MWP) in the Southern Hemisphere is uncertain because of the paucity of well-dated, high-resolution paleo-temperature records covering the past 1,000 years. We describe a new tree-ring reconstruction of Austral summer temperatures from the South Island of New Zealand, covering the past 1,100 years. This record is the longest yet produced for New Zealand and shows clear evidence for persistent above-average temperatures within the interval commonly assigned to the MWP. Comparisons with selected temperature proxies from the Northern and Southern Hemispheres confirm that the MWP was highly variable in time and space. Regardless, the New Zealand temperature reconstruction supports the global occurrence of the MWP.
Tree ring reconstructions Tasmania
[Crucifix et al. 2002]
An Earth system model of intermediate complexity, MoBidiC, has been used to simulate the transient variations in continental temperature, sea-surface temperature (SST), thermohaline circulation (THC) and sea-ice cover over the last 9000 years (9 kyr). Experiments were designed to determine (a) the deviation of the climatic system with respect to equilibrium over the last 9 kyr, (b) the individual contributions of oceans and vegetation to climatic changes, as well as the potential synergies between these components, and (c) the relative importance of precession, obliquity and CO2 concentration changes during this period. Results show a monotonous cooling trend in the northern high latitudes between 9 kyr BP and the present day, both over the oceans and the continents. North of 60°N, this cooling is noticed throughout the year, but the largest variations appear in spring and summer (up to 6 °C over continents). Along with this cooling, the model exhibits a southward shift of the northern treeline by about 600 km. Most of this shift takes place between 4 and 1 kyr BP. During this period, reorganisations of the boreal forest introduce a lag of about 200 years in the system with respect to a state in equilibrium with the external forcing. Sensitivity experiments illustrate the strong impact of this vegetation shift both on the oceans and the continents, especially in spring and early summer. However, the model exhibits a weak synergy between vegetation and ocean throughout the Holocene. Finally, a sensitivity study to the forcing components shows the dominant role of the astronomical forcing with respect to CO2, as well as the non-linear behaviour of climate in response to obliquity and precession.
HOLOCENE, EMIC, Mobidic, Forcings, Temperatures, orbital, greenhouse
[Esper et al. 2002]
Use tree ring chronologies (14) in the N. H. with Regional Curve Standardization method. Obtain estimation of T for 800-2000 AD. There are trends in the past as high as in the 20th century. Tree rings keep long frequency variability if properly treated
Last Millenium. NH temperatures. Reconstructions
[Hewitson and Crane 2002]
Application of SOMs and neural networks for synoptic climatology. Nice description and potential uses
Downscaling, neural networks, som
[Huth 2002]
Statistical downscaling of daily mean temeprature in central Europe. Similar to [Huth 1999]. Checks sensitivity of domain size and effect of inflation and randomization. Large scale temperature predictors better than circulation. Domain size of little importance. Inflation better than randomization
Statistical downscaling, daily temperature, linear methods, cca, multiple regression.
[Idso and Idso 2002]
Good example of skeptics stand out. They use the paper of [] to claim that the trends in the 2oth century are not c02 driven but are part of a millennial oscillation of which the MWP and the LIA maximum and minimum states.
Paleoclimatic reconstructions, temperature, global warming, LIA, MWP.
[Jolliffe et al. 2002]
ABSTRACT: Principal component analysis (PCA) is widely used in atmospheric science, and the resulting empirical orthogonal functions (EOFs) are often rotated to aid interpretation. In this paper 3 methods are described which provide alternatives to the standard 2-stage procedure of PCA followed by rotation. The techniques are illustrated on a small example involving sea-surface temperatures in the Mediterranean. Each method is shown to give different simplified interpretations for the major sources of variation in the data set. All 3 techniques have advantages over standard rotation.
PCA, rotation
[Lean et al. 2002]
Solar irradiance and Be14(t) depend on suns magnetic flux in different ways. Surface magnetic fields produce sunspots and faculae which alter radiative output. Sunspots and faculae account for the bulk of suns total magnetic flux, this means that annual values of total irradiance and solar magnetic flux is well correlated. A relatively small fraction of Suns magnetic flux extends into heliosphere. These open magnetic fields arise from coronall holes and are the source of the interplanetary magnetic field (IMF). IMF change flux of cosmic rays and Be14 and geomagnetic activity. They use a flux transport model to simulate the effect of solar activity on the suns total and open magnetic flux. The result that the suns total and open magnetic flux variations ar not the same suggests that cosmogenic isotope variations may not necesarilly concurrent changes in solar irradiance
Solar irradiance, solar activity, cosmogenic isotopes.
[Luterbacher et al. 2002a]
Extension of [Luterbacher et al. 1999] NAOI back to 1500 using documentary evidence, early instrumental and proxy data.
NAO index, paleo reconstructions, documentary reconstructions, historical data.
[Luterbacher et al. 2002b]
Reconstruction of gridded slp field over Europe and eastern North Atlantic. 5x5 resolution with monthly data up to 1659 and seasonal back to 1500.
Paleo reconstructions, field reconstructions, documentary reconstructions, historical data, pca regression.
[Mann and Hughes 2002]
They say [] is flawed. Warming in the 20th century is unprecedent. [Mann et al. 1999] use NH data while [] use only extratropical continental data. They say the number of series is not adequate for the use of RCS.
Last Millenium. NH temperatures. Reconstructions
[Majorowicz et al. 2002]
Canadian well temperature logs for 141 sites are analyzed and show evidence of extensive ground surface temperature (GST) warming beginning in the eighteenth and nineteenth centuries following a lengthy period of cooling (the Little Ice Age) over most of the past millennium. The method of functional space inversion (FSI) is applied to the complete set of 141 well precise temperature logs from wells located in low-conductivity clastic sediments of the western Canadian Sedimentary basin and higher thermal conductivity crystalline rocks of the Canadian Shield in central and eastern Canada. Marked regional differences in the onset of recent warming are evident (nineteenth century compared to the seventeenth to eighteenth centuries, respectively), following a prolonged cold period through earlier centuries. Analysis of spatial patterns of GST history changes across Canada based on the individual inversions of temperature logs shows a systematic east-to-west retardation in the onset of the recent warming yet a higher overall warming magnitude in western Canada in the twentieth century.
Last millennium, borehole reconstructions
[Mann and Rutherford 2002]
Climate reconstruction using pseudoproxies. They create pseudoproxies from instrumental observations adding noise with different spectral properties to the time series. It is found that to improve present reconstructions either the number of pseudoproxies is largely increased with similar signal to noise ratios or a few proxies are strategically included with higher signal-to-noise ratio.
Last Millenium. temperatures. Reconstructions
[Risk et al. 2002b]
Soils constitute the largest terrestrial source of carbon dioxide to the atmosphere, and in the context of changing global temperature and moisture patterns, it is critical that we understand the climatic controls on soil respiration. We use subsurface CO2 concentrations, surface CO2 flux and detailed physical monitoring of the subsurface regime to examine physical controls on soil CO2 production. Results indicate that subsurface CO2 production is very sensitive to the subsurface thermal regime, where relationships were robust and also stable across all land use types studied. In contrast, the thermal dependence of surface CO2 flux was much weaker. We found that soil heat content, rather than soil temperature, was the most descriptive index of the biological processes contributing to soil profile CO2 production at our study sites. Soil moisture was also found to have an important influence on subsurface CO2 production, particularly because of the relationship between moisture and soil profile diffusivity. Nondiffusive profile CO2 transport also appears to be important at these sites where the subsurface controls on transport change regularly and markedly.
CO2, soil temperatures, carbon cycle
[Risk et al. 2002a]
The temperature dependance of soil respiration has most commonly been addressed using surface flux data, despite the fact that surface flux measurements implicate CO2 transport and storage effects that may preclude robust assessments of the temperature dependence of soil respiration. Here we examine whether soil respiration might be assessed using soil profile CO2 production inferred from soil CO2 concentration profiles. Over the 9-month study period, we observed marked similarities in the temperature response of CO2 production across four study sites of contrasting vegetation cover and land use.
CO2, soil temperatures, carbon cycle
[Rodriguez-Fonseca and de Castro 2002]
Relationship between the first model of the anomalous Iberian Peninsula Northern Africa winter precipitation and previous summer SST in the North Atlantic basin.
NAO, upwelling, precipitation, seasonal predictability.
[Roy et al. 2002]
Temporal variations in surface ground temperature impart a signal to the subsurface thermal regime that is captured in borehole temperature-depth profiles. Seventy temperature-depth profiles in India, located between 12olsiand 28olsiN, are analyzed to infer past changes in ground temperature. These profiles exhibit predominantly positive anomalous temperatures relative to the background thermal regime beginning at depths of 75 150 m and increasing toward the surface. This pattern is consistent with warming over the past century. An interpretation in terms of linear surface temperature change indicates warming of about 0.9olsi±0.1olsiC over the past 150 years. Relatively complete surface air temperature (SAT) records from meteorological stations near the boreholes indicate similar rates of warming over the last century. A combined analysis of borehole temperatures and SAT records yields a long-term, preobservational mean temperature, 0.8olsi±0.1olsiC lower than the 1961 1990 mean SAT. When the most recent decade is included directly in the analysis, the average total warming in India from the early 1800s to the late 1990s is 1.2olsiC..
Climate warming, climate change, boreholes, India.
[Sokratov and Barry 2002]
Abstract: We present the results of an analysis of the observed variation in the energy balance of a soil surface at Barrow, Alaska, during 1993 1998. When combined with snow depth measurements, the data allow several stages to be distinguished in the intraseasonal variation of the snow cover effect on the temperature regime and energy balance of the underlying soil. Each stage corresponds to specific thermoinsulation effects of the snow cover in terms of the energy-balance dependence of the soil-surface on snow depth. Stages in the intraseasonal surface energy balance variation can be used as a basis for incorporating detailed snow physics in modeling of the soil freezing/thawing phenomenon and for consideration of the distributed energy balance of snow covered landscapes. Preliminary ideas are presented on applying the results obtained for nonpermafrost regions. INDEX TERMS: 3322 Meteorology and Atmospheric Dynamics: Land/atmosphere interactions; 1836 Hydrology: Hydrologic budget (1655); 3337 Meteorology and Atmospheric Dynamics: Numerical modeling and data assimilation
borehole reconstructions, sat-gst coupling
[Taylor et al. 2002]
The complexity of ecosystems can cause subtle and chaotic responses to changes in external forcing. They show that a complex ecosystem can extract information that is scattered throughout a set of meterological variables. A consequence is that biological systems can exhibit responses to subtle climatic signals, signals that may be distinct from those that are the most apparent.
NAO, gulf stream, echosystem interactions.
[Turcotte and Schubert 2002]
Geodynamics
Geodynamics, book
[Vincent et al. 2002]
Homogenization of temperature data over Canada. Ilustrates adjustments of monthly and daily time series from annual corrections..

Homogeneity, temperature, Canada.
[Wanner and Lutherbacher 2002]
The LOTRED approach. Long term recostruction and diagnostics (LOTRED). The idea is to produce a set of reconstructed fields for the state variables in the line of a reanalysis for the last centuries from documentary and natural proxies.
Last Millenium. European temperatures. LOTRED. Paleoreanalysis.
[Waple et al. 2002]
Comparison of sensitivity to solar forcing in [Mann et al. 1998] et al reconstructions and in the MPI and GISS model. Nice description and discussion of sensitivity assessment.
Solar forcing, GCM paleoclimate simulations, sensitivity, climate reconstructions.
[Zorita and González-Rouco 2002]
Validation of the NAO recostructions using the Columbus integrations. Which proxies are best, temperature or precipitation sensitive?
AOGCM, paleoclimate, reconstructions, NH temperature