Climate Blog and News Recap: 2011 02 19
Update 20110220: I’ve added both some older and newer technical links to the S09/O10 information and will continue to do so as good links become available (or I find interesting old ones).
The “Tribe-said/Team-said” BS seems to be simmering down some and a couple of blogs are looking under the hood to see what all the fuss is about (technically) in the Steig 2009 / ODonnell 2010 kerfluffle.
kgnd & Cross-Validation: PART II – Parting Thoughts O’Donnell @ the Air Vent
kgnd & Cross-Validation ODonnell @ the Air Vent
Antarctic, RO10, Steig and TempLS Stokes @ Moyhu
Ryan’s Code – testing. Stokes @ Moyhu
Ryan’s Code – S09 with more PCs Stokes @ Moyhu
Ryan’s Code Stokes @ Moyhu
Sensitivity Test: O’Donnell’s idea Lucia @ The Blackboard
A Calmer Conversation with the Nail O’Donnell at The Air Vent
EIV/TLS Regression – Why Use It? RomanM at Statistics and Other Things
The Two-and-One-Half PC Solution RomanM at Statistics and Other Things
Ridge Regression Tamino @ Open Mind
Real Climate and Climate Progress comment on two papers dealing with flooding and precipitation. Dr. Pielke Jr casts these in contrast with flood damage and streamflows. Dr Curry find this kind of analysis “totally unconvincing”. Eschenbach has a reply cast in the usual WUWT scathing tone.:
Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000
Pall, Aina, Stone, Stott, Nozawa, Hilberts, Lohmann & Allen (2011)
Human contribution to more-intense precipitation extremes
Min, Zhang, Zwiers & Heger (2011)
About twenty global climate models have been run for the IPCC Fourth Assessment Report (AR4) in order to predict climate change due to anthropogenic activities. Evaluating these models is an important step to establish confidence in climate projections. Model evaluation however is often performed on a grid-point basis despite the fact that models are known to often be unreliable at such small spatial scales. In this study, the annual mean values of surface air temperature and precipitation are analyzed. Using a spatial smoothing technique with a variable scale parameter it is shown that the intermodel spread as well as model errors from observations are reduced as the characteristic smoothing scale increases. At the same time the ability to reproduce small scale features is reduced and the simulated patterns become fuzzy. Depending on the variable of interest, the location and the way data is aggregated, different optimal smoothing scales from the grid-point size to about 2000 km are found to give good agreement with present-day observation, yet retain most regional features of the climate signal. Higher model resolution surprisingly does not imply much better agreement with temperature observations, in particular with stronger smoothing, and resolving smaller scales therefore does not necessarily seem to improve the simulation of large scale climate features. Similarities in mean temperature and precipitation fields for a pair of models in the ensemble persist locally for about a century into the future, providing some justification for subtracting control errors in the models. Large scale to global errors however are not well preserved over time, consistent with a poor constraint of the present day climate on the simulated global temperature and precipitation response.
Spatial Scale Dependence of Climate Model Performance in the CMIP3 Ensemble (Journal of Climate)
This study describes the main circulation patterns (CP) in the Amazonian Basin over the 1975–2002 period and their relationship with rainfall variability. CPs in the Amazonian Basin have been computed for each season from the ERA-40 daily 850 hPa winds using an approach combining artificial neural network (Self Organizing Maps) and Hierarchical Ascendant Classification. A 6 to 8 cluster solutions (depending on the season considered) is shown to yield an integrated view of the complex regional circulation variability. … This analysis clearly illustrates the existing connections between the southern and northern part of the Amazonian Basin in terms of regional circulation/rainfall patterns. The identification of these CPs provide useful information to understand local rainfall variability and could hence be used to better understand the influence of these CPs on the hydrological variability in the Amazonian Basin.
…Given that the Köppen-Trewartha (K-T) climate classification is based on reliable variations of land-surface types (especially vegetation), this study used the K-T scheme to evaluate climate changes and their impact on vegetation for the Arctic (north of 50°N) by analyzing observations as well as model simulations for the period 1900–2099. The models include 16 fully coupled global climate models from the Intergovernmental Panel on Climate Change Fourth Assessment. … the projected redistributions of K-T climate types also differ regionally. In northern Europe and Alaska, the warming may cause more rapid expansion of temperate climate types. …
We present results from multiple comprehensive models used to simulate an aggressive mitigation scenario based on detailed results of an Integrated Assessment Model. The experiment employs ten global climate and Earth System models (GCMs and ESMs) and pioneers elements of the long-term experimental design for the forthcoming 5th Intergovernmental Panel on Climate Change assessment….
… In this paper, we analyzed the temporal and spatial trends in the frequency of extreme minimum temperatures during the warm season (from May to September) during 1956–2005 in Northeast China. Abrupt climatic changes were identified using the Mann–Kendall test. The results show that the frequency of extreme minimum temperature days during the warm season in Northeast China decreases significantly from 1956 to 2005 with a background of climate warming. The highest number of extreme minimum temperature days occurred in the 1970s and 1980s, and there was an abrupt climatic change in 1993. The spatial analysis identified that the north and southeast of the region experienced a larger decrease in the number of extreme low temperature days than the west and south of the region. Rice, sorghum, corn, and soybeans are most vulnerable to cold damage. In severe low temperature years, the average crop yield was reduced by 15.2% in Northeast China.
A new analysis of sulfur emissions appearing in the journal Atmospheric Chemistry and Physics shows that after declining for a decade, worldwide emissions rose again in 2000 due largely to international shipping and a growing Chinese economy. An accurate read on sulfur emissions will help researchers predict future changes in climate and determine present day effects on the atmosphere, health and the environment
Worldwide sulfur emissions rose between 2000-2005, after decade of decline (PHYSorg.com: Space & Earth)
Paleoenvironmental records from a number of permafrost sections and lacustrine cores from the Laptev Sea region dated by several methods (14C-AMS, TL, IRSL, OSL and 230Th/U) were analyzed for pollen and palynomorphs. The records reveal the environmental history for the last ca 200 kyr. For interglacial pollen spectra, quantitative temperature values were estimated using the best modern analogue method. Sparse grass-sedge vegetation indicating arctic desert environmental conditions existed prior to 200 kyr ago. Dense, wet grass-sedge tundra habitats dominated during an interstadial ca 200–190 kyr ago, reflecting warmer and wetter summers than before. Sparser vegetation communities point to much more severe stadial conditions ca 190–130 kyr ago. Open grass and Artemisia communities with shrub stands (Alnus fruticosa, Salix, Betula nana) in more protected and moister places characterized the beginning of the Last Interglacial indicate climate conditions similar to present. Shrub tundra (Alnus fruticosa and Betula nana) dominated during the middle Eemian climatic optimum, when summer temperatures were 4–5 °C higher than today. Early-Weichselian sparse grass-sedge dominated vegetation indicates climate conditions colder and dryer than in the previous interval. Middle Weichselian Interstadial records indicate moister and warmer climate conditions, for example, in the interval 40–32 kyr BP Salix was present within dense, grass-sedge dominated vegetation. Sedge-grass-Artemisia-communities indicate that climate became cooler and drier after 30 kyr BP, and cold, dry conditions characterized the Late Weichselian, ca 26–16 kyr BP, when grass-dominated communities with Caryophyllaceae, Asteraceae, Cichoriaceae, Selaginella rupestris were present. From 16 to 12 kyr BP, grass-sedge communities with Caryophyllaceae, Asteraceae, and Cichoriaceae indicate climate was significantly warmer and moister than during the previous interval. The presence of Salix and Betula reflect temperatures about 4 °C higher than present at about 12–11 kyr BP, during the Allerød interval, but shrubs were absent in the Younger Dryas interval, pointing to a deterioration of climate conditions. Alnus fruticosa, Betula nana, Poaceae, and Cyperaceae dominate early Holocene spectra. Reconstructed absolute temperature values were substantially warmer than present (up to 12 °C). Shrubs gradually disappeared from coastal areas after 7.6 kyr BP when vegetation cover became similar to modern. A comparison of proxy-based paleoenvironmental reconstructions with the simulations performed by an Earth system model of intermediate complexity (CLIMBER-2) show good accordance between the regional paleodata and model simulations, especially for the warmer intervals.
Rising sea levels could threaten an average of 9 percent of the land within 180 U.S. coastal cities by 2100, according to new research led by University of Arizona scientists.
Rising seas will affect major US coastal cities by 2100 (PHYSorg.com: Space & Earth)
The tropical, warm, and equable climate of the Jurassic world is regularly challenged by geoscientists, especially since oxygen isotopes (δ18O) of fossil hardparts have been used to reconstruct the paleotemperature history of seawater. By applying the innovative “SiZer” (significant zero crossings of the derivatives) statistical approach to a newly compiled δ18O database for the Jurassic, we demonstrate the occurrence of major and multiscale δ18O changes mainly related to climate disturbances. For the first time, two long-term anomalies in δ18O are identified during the Toarcian and the Late Jurassic, in conjunction with intensive volcanism in large igneous provinces. These results support a strong influence of repeated volcanic pulses on the modulation of pCO2, temperatures, and polar ice cap volumes over protracted periods. At shorter time scales, 13 relatively rapid (0.5–1 m.y.) and significant warming and cooling events are identified, the causes of which include transient fluctuations in greenhouse gas concentrations related to still-debated mechanisms.
The global CO2 discharge from subaerial volcanism has been estimated at ∼300 Mt yr−1. However, estimates of CO2 emissions from volcanic lakes have not been considered. In order to improve this information, extensive research on CO2 emissions of volcanic lakes worldwide has been performed. The observed normalized average CO2 emission rates increase from alkaline (5.5 t km−2 d−1), to neutral (201.2 t km−2 d−1), to acid (614.2 t km−2 d−1) in volcanic lakes. Taking into account (1) normalized CO2 emission rates, (2) the number of volcanic lakes in the world (∼769), and (3) the fraction and average areas of the investigated alkaline, neutral, and acid volcanic lakes, the estimated global CO2 emission from volcanic lakes is 117 ± 19 Mt yr−1, with 94 ± 17 Mt yr−1 as deep-seated CO2. This study highlights the importance of a revision of the actual global CO2 discharge from subaerial volcanism.
Global CO2 emission from volcanic lakes (Geology)
The deep-ocean marine isotope record and the Antarctic and Greenland ice caps record numerous glacial and interglacial cycles since the middle Pleistocene, and yet evidence for similar numbers of ice-sheet advances over the continent and shallow shelves of northwest Europe is absent. Here, we document seven generations of regionally correlatable subglacial tunnel valleys that record the geomorphic imprint of ice sheets traversing the North Sea basin between ca. 500 and 40 ka, consistent with that predicted by proxy records of glacial and interglacial climate change. …These results imply a more complicated glacial history for northwest Europe and more glaciations than the three-glaciation model traditionally interpreted from the terrestrial record for the past 500 k.y. Our data provide the most complete documentary evidence for repeated advance and retreat of the northwest European ice sheets since the middle Pleistocene, and for the first time indicate that terrestrial ice-sheet advances in the North Sea can be matched in number with the cold events recorded in oceanic and/or ice-core proxies of climate change over the past 500 k.y.
While governments debate about potential policies that might curb the emission of greenhouse gases, new University of Washington research shows that the world is already committed to a warmer climate because of emissions that have occurred up to now.
If greenhouse gas emissions stopped now, Earth still would likely get warmer: study (PHYSorg.com: Space & Earth)
After interference from an unexpected climate event, La Nina is expected to re-establish her influence over weather patterns in the Southeast and bring warm and dry weather to the region for the rest of the winter, according to officials at the Florida Climate Center at The Florida State University.
Climatologists: La Nina may bring warm late winter to Southeast (PHYSorg.com: Space & Earth)
We present a new method of analyzing model results to help identify the sensitivity of the location of different paleodust records to estimate local to regional scale variability of dust and climate variables. We use model simulations of global dust distribution from the last glacial maximum, preindustrial, current, and predicted future. The dust model has been previously shown to match available observational data for the current and last glacial maximum climate. … For Greenland, the model predicts a possible shift from dominantly wet deposition under modern conditions to dominantly dry deposition during glacial climate conditions indicating that deposition may be better suited to capture dustiness variability under LGM conditions in Greenland. The model also identifies specific regions that are not well covered by observations for glacial/interglacial or anthropocene dust variability. In addition, we evaluate the modeled relative slope of the location of these cores to determine regions that would provide ideal localities for pursuing records that would provide easily interpretable paleo-proxy records of regional dustiness.
Model insight into glacial–interglacial paleodust records (Quaternary science reviews)
Variations of temperature and precipitation extremes were investigated under the rapid warming over China since the 1990 s. Six percentile-based indices derived from daily minimum and maximum surface air temperature and daily precipitation amount at 532 meteorological observing stations were computed and compared in two periods of 1960–1989 and 1990–2007. For China as a whole, the occurrence frequencies of annual cold nights and warm nights derived from daily minimum temperature have changed by − 3.8% and 2.8% respectively, while annual cold days and warm days derived from daily maximum temperature have experienced relatively smaller variations of − 2.1% and 1.8% in recent two decades. Notable frequency decreases of cold extremes were found in North China and Northeast China, whereas warm extremes increased profoundly in South China, Southwest China and Northwest China. Frequency decreases of cold extremes mainly occurred in winter. However, warm extremes displayed both remarkable frequency increases in winter and summer…. Precipitation extremes were found largely increased in the rainy season from April to September, thus exhibiting similar spatial patterns to that in annual. As in the dry season from October to next March, significant increases of precipitation extremes were detected in Northeast China and North China instea
Variations of Temperature and Precipitation Extremes in Recent Two Decades over China (Atmospheric research)
Up to two-thirds of Earth’s permafrost likely will disappear by 2200 as a result of warming temperatures, unleashing vast quantities of carbon into the atmosphere, says a new study by the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences.
Thawing permafrost likely will accelerate global warming (PHYSorg.com: Space & Earth)
NSIDC bombshell: Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100 Romm @ Climate Progress
In an ensemble of general circulation models, the global mean albedo significantly decreases in response to strong CO2 forcing. In some of the models, the magnitude of this positive feedback is as large as the CO2 forcing itself. The models agree well on the surface contribution to the trend, due to retreating snow and ice cover, but display large differences when it comes to the contribution from shortwave radiative effects of clouds. The “cloud contribution” defined as the difference between clear-sky and all-sky albedo anomalies and denoted as ΔCC is correlated with equilibrium climate sensitivity in the models (correlation coefficient 0.76), indicating that in high sensitivity models the clouds to a greater extent act to enhance the negative clear-sky albedo trend, whereas in low sensitivity models the clouds rather counteract this trend. As a consequence, the total albedo trend is more negative in more sensitive models (correlation coefficient 0.73). This illustrates in a new way the importance of cloud response to global warming in determining climate sensitivity in models. The cloud contribution to the albedo trend can primarily be ascribed to changes in total cloud fraction, but changes in cloud albedo may also be of importance
Planetary albedo in strongly forced climate, as simulated by the CMIP3 models (Theoretical and Applied Climatology)
This study aims at presenting various methodologies to separate the reproducible and irreproducible components of seasonal and intraseasonal climate variability simulated by a regional climate model over Southern Africa (south of 15°S), during an austral summer rainy season representative of the climatology. To that end, a 30-member ensemble simulation is performed using WRF laterally forced by the ERA40 reanalyses. …
This study investigates multivariable and multiscalar climate-δ18O relationships, through the use of statistical modeling and simulation. Three simulations, of increasing complexity, are used to generate time series of daily precipitation δ18O. The first simulation uses a simple local predictor (daily rainfall amount). The second simulation uses the same local predictor plus a larger-scale climate variable (a daily NAO index), and the third simulation uses the same local and non-local predictors, but with varying seasonal effect. Since these simulations all operate at the daily timescale, they can be used to investigate the climate-δ18O patterns that arise at daily-interannual timescales. …The methodology introduced here can potentially be applied to historic monthly δ18O data, to better understand how multiple-integrated influences at short timescales give rise to climate-δ18O patterns at monthly-interannual timescales.
Hundreds of planets have now been detected outside our solar system. So far, very little is known about the physical conditions on these fascinating objects. Kevin Heng from the Institute for Astronomy at ETH Zurich is attempting to close this gap with sophisticated model stimulations.
Violent storms on alien planets (PHYSorg.com: Space & Earth)
Satellite observations are analyzed to examine the correlations between aerosols and the tropical tropopause layer (TTL) temperature and water vapor. We focus on two regions, both of which are important pathways for the mass transport from the troposphere to the stratosphere and over which Asian pollution prevails: South and East Asia during boreal summer, and the maritime continent during boreal winter. Using the upper tropospheric carbon monoxide measurements from the Aura Microwave Limb Sounder as a proxy of aerosols to classify ice clouds as polluted or clean, we find that polluted clouds have smaller ice effective radius, and higher temperature and specific humidity near the tropopause than clean clouds. The increase in water vapor appears to be related to the increase in temperature, as a result of increased aerosols. Meteorological differences between the clouds cannot explain the differences in temperature and water vapor for the polluted and clean clouds. We hypothesize that aerosol semi-direct radiative heating and/or changes in cirrus radiative heating, resulting from aerosol microphysical effects on clouds, may contribute to the increased TTL temperature and thus increased water vapor in the polluted clouds.
Observed Increase of TTL Temperature and Water Vapor in Polluted Clouds over Asia (Journal of Climate)
Previous versions of GISS climate models have either used formulations of Rayleigh drag to represent unresolved gravity wave interactions with the model resolved flow or have included a rather complicated treatment of unresolved gravity waves that, while being climate interactive, involved the specification of a relatively large number of parameters that were not well constrained by observations and also was computationally very expensive. Here, we introduce a relatively simple and computationally efficient specification of unresolved orographic and non-orographic gravity waves and their interaction with the resolved flow. We show comparisons of the GISS model winds and temperatures with no gravity wave parametrization; with only orographic gravity wave parameterization; and with both orographic and non-orographic gravity wave parameterizations to illustrate how the zonal mean winds and temperatures converge toward observations. We also show that the specifications of orographic and non-orographic gravity waves must be different in the Northern and Southern Hemispheres. We then show results where the non-orographic gravity wave sources are specified to represent sources from convection in the Intertropical Convergence Zone and spontaneous emission from jet imbalances. Finally, we suggest a strategy to include these effects in a climate dependent manner.
New Gravity Wave Treatments for GISS Climate Models (Journal of Climate)
Siberia’s Lake Baikal, the world’s oldest, deepest, and largest freshwater lake, has provided scientists with insight into the ways that climate change affects water temperature, which in turn affects life in the lake. The study is published in the journal PLoS ONE today.
World’s largest lake sheds light on climate change (PHYSorg.com: Space & Earth)
Pour enough magma out through Earth’s crust, and you can change the atmosphere radically.
Really big eruptions, lots and lots of CO2 (PHYSorg.com: Space & Earth)