Hemispheric Scale Research Articles

The climatic effects of modifying cirrus clouds in a climate engineering framework

AbstractThe climatic effects of climate engineering—or geoengineering—via cirrus cloud thinning are examined. Thinner cirrus clouds can allow more outgoing longwave radiation to escape to space, potentially cooling the climate. The cloud properties and climatic effects due to perturbing the ice crystal fall speed are investigated in a set of hemispheric scale sensitivity experiments with the Community Earth System Model. It is found that increasing the ice crystal fall speed, as an analog to cirrus cloud seeding, depletes high‐level clouds and reduces the longwave cloud forcing. Deliberate depletion of cirrus clouds increases outgoing longwave radiation, reduces the upper tropospheric water vapor, and cools the climate. Global cirrus cloud thinning gave a net cloud forcing change of −1.55 W m−2 and a global annual mean temperature change of −0.94 K. Though there is negligible change in the global annual mean precipitation (−0.001 mm/d), the spatially nonhomogeneous forcing induces circulation changes and hence remote climate changes. Climate engineering the Southern Hemisphere only results in a northward shift of the Intertropical Convergence Zone and possible Sahelian drought alleviation, while targeting the Northern Hemisphere alone causes a greater cooling. It was found that targeting cirrus clouds everywhere outside of the tropics results in changes to the circulation and precipitation even in the nonclimate engineered regions, underscoring the risks of remote side effects and indeed the complexity of the climate system.

A study of the contribution of mass elevation effect to the altitudinal distribution of timberline in the Northern Hemisphere

Alpine timberline, as the “ecological transition zone,” has long attracted the attention of scientists in many fields, especially in recent years. Many unitary and dibasic fitting models have been developed to explore the relationship between timberline elevation and latitude or temperature. However, these models are usually on regional scale and could not be applied to other regions; on the other hand, hemispherical-scale and continental-scale models are usually based on about 100 timberline data and are necessarily low in precision. The present article collects 516 data sites of timberline, and takes latitude, continentality and mass elevation effect (MEE) as independent variables and timberline elevation as dependent variable to develop a ternary linear regression model. Continentality is calculated using the meteorological data released by WorldClim and mountain base elevation (as a proxy of mass elevation effect) is extracted on the basis of SRTM 90-meter resolution elevation data. The results show that the coefficient of determination (R2) of the linear model is as high as 0.904, and that the contribution rate of latitude, continentality and MEE to timberline elevation is 45.02% (p=0.000), 6.04% (p=0.000) and 48.94% (p=0.000), respectively. This means that MEE is simply the primary factor contributing to the elevation distribution of timberline on the continental and hemispherical scales. The contribution rate of MEE to timberline altitude differs in different regions, e.g., 50.49% (p=0.000) in North America, 48.73% (p=0.000) in the eastern Eurasia, and 43.6% (p=0.000) in the western Eurasia, but it is usually very high.

The Nonlinear and Nonlocal Nature of Climate Feedbacks

Abstract The climate feedback framework partitions the radiative response to climate forcing into contributions from individual atmospheric processes. The goal of this study is to understand the closure of the energy budget in as much detail and precision as possible, within as clean an experimental setup as possible. Radiative kernels and radiative forcing are diagnosed for an aquaplanet simulation under perpetual equinox conditions. The role of the meridional structure of feedbacks, heat transport, and nonlinearities in controlling the local climate response is characterized. Results display a combination of positive subtropical feedbacks and polar amplified warming. These two factors imply a critical role for transport and nonlinear effects, with the latter acting to substantially reduce global climate sensitivity. At the hemispheric scale, a rich picture emerges: anomalous divergence of heat flux away from positive feedbacks in the subtropics; nonlinear interactions among and within clear-sky feedbacks, which reinforce the pattern of tropical cooling and high-latitude warming tendencies; and strong ice-line feedbacks that drive further amplification of polar warming. These results have implications for regional climate predictability, by providing an indication of how spatial patterns in feedbacks combine to affect both the local and nonlocal climate response, and how constraining uncertainty in those feedbacks may constrain the climate response.

Volcanic cooling signal in tree ring temperature records for the past millennium

AbstractTree rings are an important proxy for understanding the timing and environmental consequences of volcanic eruptions as they are precisely dated at annual resolution and, particularly in tree line regions of the world, sensitive to cold extremes that can result from climatically significant volcanic episodes. Volcanic signals have been detected in ring widths and by the presence of frost‐damaged rings, yet are often most clearly and quantitatively represented within maximum latewood density series. Ring width and density reconstructions provide quantitative information for inferring the variability and sensitivity of the Earth's climate system on local to hemispheric scales. After a century of dendrochronological science, there is no evidence, as recently theorized, that volcanic or other adverse events cause such severely cold conditions near latitudinal tree line that rings might be missing in all trees at a given site in a volcanic year (“stand‐wide” missing rings), resulting in misdating of the chronology. Rather, there is a clear indication of precise dating and development of rings in at least some trees at any given site, even under adverse cold conditions, based on both actual tree ring observations and modeling analyses. The muted evidence for volcanic cooling in large‐scale temperature reconstructions based at least partly on ring widths reflects several factors that are completely unrelated to any misdating. These include biological persistence of such records, as well as varying spatial patterns of response of the climate system to volcanic events, such that regional cooling, particularly for ring widths rather than density, can be masked in the large‐scale reconstruction average.

The Little Ice Age climate of New Zealand reconstructed from Southern Alps cirque glaciers: a synoptic type approach

Little Ice Age (LIA) austral summer temperature anomalies were derived from palaeoequilibrium line altitudes at 22 cirque glacier sites across the Southern Alps of New Zealand. Modern analog seasons with temperature anomalies akin to the LIA reconstructions were selected, and then applied in a sampling of high-resolution gridded New Zealand climate data and global reanalysis data to generate LIA climate composites at local, regional and hemispheric scales. The composite anomaly patterns assist in improving our understanding of atmospheric circulation contributions to the LIA climate state, allow an interrogation of synoptic type frequency changes for the LIA relative to present, and provide a hemispheric context of the past conditions in New Zealand. An LIA summer temperature anomaly of −0.56 °C (±0.29 °C) for the Southern Alps based on palaeo-equilibrium lines compares well with local tree-ring reconstructions of austral summer temperature. Reconstructed geopotential height at 1,000 hPa (z1000) suggests enhanced southwesterly flow across New Zealand occurred during the LIA to generate the terrestrial temperature anomalies. The mean atmospheric circulation pattern for summer resulted from a crucial reduction of the ‘HSE’-blocking synoptic type (highs over and to the west of NZ; largely settled conditions) and increases in both the ‘T’- and ‘SW’-trough synoptic types (lows passing over NZ; enhanced southerly and southwesterly flow) relative to normal. Associated land-based temperature and precipitation anomalies suggest both colder- and wetter-than-normal conditions were a pervasive component of the base climate state across New Zealand during the LIA, as were colder-than-normal Tasman Sea surface temperatures. Proxy temperature and circulation evidence were used to corroborate the spatially heterogeneous Southern Hemisphere composite z1000 and sea surface temperature patterns generated in this study. A comparison of the composites to climate mode archetypes suggests LIA summer climate and atmospheric circulation over New Zealand was driven by increased frequency of weak El Nino-Modoki in the tropical Pacific and negative Southern Annular Mode activity.

Dependence of the climate prediction skill on spatiotemporal scales: Internal versus radiatively-forced contribution

[1] This article aims at quantifying the improvement in climate prediction skill as a function of temporal (from monthly to decadal) and spatial scales (from grid point to global) when initializing a perturbed parameter ensemble of the Hadley Centre Climate Model. The focus is on near-surface temperature and precipitation in the Tropical band, the Northern and Southern hemispheres. For temperature, the forecast system reproduces the dominant impact of the external forcing at global spatial scale and at decadal time scales. There are significant improvements with initialization for the first 40 forecast months in the global and tropical domains. In the Northern (Southern) hemisphere, the initialization increases the skill in the first 12 (20) months on regional but not hemispheric scales. The initialization has a stronger impact in the model variants with a weaker global-mean temperature trend. For precipitation, the initialization corrects the negative correlation found at global and tropical scales.

Temporal and spatial variability of the global water balance

An analysis of simulated global water-balance components (precipitation [P], actual evapotranspiration [AET], runoff [R], and potential evapotranspiration [PET]) for the past century indicates that P has been the primary driver of variability in R. Additionally, since about 2000, there have been increases in P, AET, R, and PET for most of the globe. The increases in R during 2000 through 2009 have occurred despite unprecedented increases in PET. The increases in R are the result of substantial increases in P during the cool Northern Hemisphere months (i.e. October through March) when PET increases were relatively small; the largest PET increases occurred during the warm Northern Hemisphere months (April through September). Additionally, for the 2000 through 2009 period, the latitudinal distribution of P departures appears to co-vary with the mean P departures from 16 climate model projections of the latitudinal response of P to warming, except in the high latitudes. Finally, changes in water-balance variables appear large from the perspective of departures from the long-term means. However, when put into the context of the magnitudes of the raw water balance variable values, there appears to have been little change in any of the water-balance variables over the past century on a global or hemispheric scale.

Stratospheric ozone depletion: a key driver of recent precipitation trends in South Eastern South America

On a hemispheric scale, it is now well established that stratospheric ozone depletion has been the principal driver of externally forced atmospheric circulation changes south of the Equator in the last decades of the 20th Century. The impact of ozone depletion has been felt over the entire hemisphere, as reflected in the poleward drift of the midlatitude jet, the southward expansion of the summertime Hadley cell and accompanying precipitation trends deep into the subtropics. On a regional scale, however, surface impacts directly attributable to ozone depletion have yet to be identified. In this paper we focus on South Eastern South America (SESA), a region that has exhibited one of the largest wetting trends during the 20th Century. We study the impact of ozone depletion on SESA precipitation using output from 6 different climate models, spanning a wide range of complexity. In all cases we contrast pairs of model integrations with and without ozone depletion, but with all other forcings identically specified. This allows for unambiguous attribution of the computed precipitation trends. All 6 climate models consistently reveal that stratospheric ozone depletion results in a significant wetting of SESA over the period 1960–1999. Taken as a whole, these model results strongly suggest that the impact of ozone depletion on SESA precipitation has been as large as, and quite possibly larger than, the one caused by increasing greenhouse gases over the same period.

Historical evolution of global and regional surface air temperature simulated by FGOALS-s2 and FGOALS-g2: How reliable are the model results?

In order to assess the performance of two versions of the IAP/LASG Flexible Global Ocean-AtmosphereLand System (FGOALS) model, simulated changes in surface air temperature (SAT), from natural and anthropogenic forcings, were compared to observations for the period 1850–2005 at global, hemispheric, continental and regional scales. The global and hemispheric averages of SAT and their land and ocean components during 1850–2005 were well reproduced by FGOALS-g2, as evidenced by significant correlation coefficients and small RMSEs. The significant positive correlations were firstly determined by the warming trends, and secondly by interdecadal fluctuations. The abilities of the models to reproduce interdecadal SAT variations were demonstrated by both wavelet analysis and significant positive correlations for detrended data. The observed land–sea thermal contrast change was poorly simulated. The major weakness of FGOALS-s2 was an exaggerated warming response to anthropogenic forcing, with the simulation showing results that were far removed from observations prior to the 1950s. The observations featured warming trends (1906–2005) of 0.71, 0.68 and 0.79 ◦ C (100 yr) −1 for global, Northern and Southern Hemispheric averages, which were overestimated by FGOALS-s2 [1.42, 1.52 and 1.13 ◦ C (100 yr) −1 ] but underestimated by FGOALS-g2 [0.69, 0.68 and 0.73 ◦ C (100 yr) −1 ]. The polar amplification of the warming trend was exaggerated in FGOALSs2 but weakly reproduced in FGOALS-g2. The stronger response of FGOALS-s2 to anthropogenic forcing was caused by strong sea-ice albedo feedback and water vapor feedback. Examination of model results in 15 selected subcontinental-scale regions showed reasonable performance for FGOALS-g2 over most regions. However, the observed warming trends were overestimated by FGOALS-s2 in most regions. Over East Asia, the meridional gradient of the warming trend simulated by FGOALS-s2 (FGOALS-g2) was stronger (weaker) than observed.

Phenological matching across hemispheres in a long‐distance migratory bird

AbstractAimIn the Northern Hemisphere, bird migration from the tropic to the temperate zone in spring is thought to proceed at a rate determined in large part by local phenology. In contrast, little is understood about where birds go or the factors that determine why they move or where they stop during the post‐breeding period.LocationStudy sites were in Oregon, Nebraska and Vermont, and location data we collected extend south to Argentina.MethodsWe deployed light‐level geolocators on individual Bobolinks from three populations across the breeding range and compare their southbound movement phenology to austral greening as indicated by the Normalized Difference Vegetation Index.ResultsBobolinks from all breeding populations synchronously arrived and remained for up to several weeks in two sequential, small non‐breeding areas that were separated by thousands of kilometres, before staging for pre‐alternate moult. Similar to the migration patterns of birds to northern breeding areas, movements into the Southern Hemisphere corresponded to increasing primary productivity.Main conclusionsOur findings suggest that the Bobolink's southbound migration is broadly constrained by resource availability, and its non‐breeding distribution has been shaped by the seasonal phenology of grasslands in both time and space. This is the first documentation of individual birds from across a continental breeding range exhibiting phenological matching during their post‐breeding southward migration. Known conservation threats overlap temporally and spatially with large concentrations of Bobolinks, and should be closely examined. We emphasize the need to consider how individuals move and interact with their environment throughout their annual cycle and over hemispheric scales.

Migration Tendency Delays Distributional Response to Differential Survival Prospects along a Flyway

When populations grow or decline, habitat selection may change due to local density-dependent processes, such as site dependence and interference. In seasonally migrating animals, nonbreeding distributions may be determined through these mechanisms of density dependence, which we examine here at a hemispheric scale for a long-distance migrating bird. Using summer and winter resightings of 2,095 Eurasian spoonbills Platalea leucorodia leucorodia that were ringed in the Netherlands during 16 years of fast population growth, we show that neither site dependence nor interference fully explains their patterns of survival and winter distribution. Within their three main wintering areas, annual survival decreased with an increase in population size. While survival was consistently higher in the two European wintering areas (France, Iberia), most spoonbills migrated onward to winter in west Africa. The number of birds wintering in Europe increased, but not enough to maximize annual survival. We conclude that a constraint of tradition (their "migration tendency") inhibits birds from changing their migratory habits. We pose that this phenomenon may similarly constrain other migratory populations from rapidly responding to large-scale climate- and/or human-driven habitat changes at their wintering grounds.

Large-scale temperature response to external forcing in simulations and reconstructions of the last millennium

Abstract. Understanding natural climate variability and its driving factors is crucial to assessing future climate change. Therefore, comparing proxy-based climate reconstructions with forcing factors as well as comparing these with paleoclimate model simulations is key to gaining insights into the relative roles of internal versus forced variability. A review of the state of modelling of the climate of the last millennium prior to the CMIP5–PMIP3 (Coupled Model Intercomparison Project Phase 5–Paleoclimate Modelling Intercomparison Project Phase 3) coordinated effort is presented and compared to the available temperature reconstructions. Simulations and reconstructions broadly agree on reproducing the major temperature changes and suggest an overall linear response to external forcing on multidecadal or longer timescales. Internal variability is found to have an important influence at hemispheric and global scales. The spatial distribution of simulated temperature changes during the transition from the Medieval Climate Anomaly to the Little Ice Age disagrees with that found in the reconstructions. Thus, either internal variability is a possible major player in shaping temperature changes through the millennium or the model simulations have problems realistically representing the response pattern to external forcing. A last millennium transient climate response (LMTCR) is defined to provide a quantitative framework for analysing the consistency between simulated and reconstructed climate. Beyond an overall agreement between simulated and reconstructed LMTCR ranges, this analysis is able to single out specific discrepancies between some reconstructions and the ensemble of simulations. The disagreement is found in the cases where the reconstructions show reduced covariability with external forcings or when they present high rates of temperature change.

The compatibility of agricultural intensification in a global hotspot of smallholder agrobiodiversity (Bolivia)

Integrating the conservation of biodiversity by smallholder farmers with agricultural intensification is increasingly recognized as a leading priority of sustainability and food security amid global environmental and socioeconomic change. An international research project investigated the smallholder agrobiodiversity of maize (corn) in a global hotspot (Bolivia) undergoing significant intensification. Peach-based intensification was pronounced (300-400%) and prolonged (2000-2010) in study areas. Intensification and maize agrobiodiversity were found to co-occur within smallholder landscapes. Interactions of these field systems did not trigger land-change tipping points leading to landrace extirpation. By 2010 maize landraces in the study areas still demonstrated high levels of taxonomic and ecological biodiversity and contributed significantly to this crop's agrobiodiversity at national (31%) and hemispheric (3%) scales. Social and ecological resilience and in situ conservation of the maize agrobiodiversity by Bolivian smallholders was enabled through robust linkages to off-farm migration; resource access and asset capabilities among both traditional and nontraditional growers; landrace agroecology and food uses; and innovative knowledge and skills. The smallholders' resilience resulting from these linkages was integral to the conditional success of the in situ conservation of maize agrobiodiversity. Environment-development interactions both enabled smallholders' agrobiodiversity resilience and influenced the limits and vulnerability of agrobiodiversity. Scientific policy recommendations regarding land-use planning and sustainability analysis are targeted to specific Río+20 priorities for agrobiodiversity.

Influence of emissions on regional atmospheric mercury concentrations

Mercury is a global pollutant that is rapidly transported in the atmosphere. Unlike the majority of air pollutants the background concentrations of mercury play a major role for the atmospheric concentrations on a hemispheric scale. In this study the influence of regional anthropogenic emissions in comparison to the global emissions on mercury concentrations over Europe are investigated. For this purpose an advanced threedimensional model system is used that consists of three components. The emission model SMOKE-EU, the meteorological model COSMO-CLM, and the chemistry transport model (CTM) CMAQ. A variety of sensitivity runs is performed in order to determine the influence of different driving factors (i.e. boundary conditions, anthropogenic and natural emissions, emission factors, meteorological fields) on the atmoshperic concentrations of different mercury species. This study is part of the European FP7 project GMOS (Global Mercury Observation System). The aim is to identify the most important drivers for atmospheric mercury in order to optimize future regional modelling studies in the course of the GMOS project. Moreover, the model results are used to determine areas of interest for air-plane based in-situ measurements which are also part of GMOS.

The UNEP Fate And Transport Partnership Area: an overview of seven years activity and future plans

The United Nations Environment Programme Mercury Air Transport and Fate Research Partnership Area (UNEP F&T) started its activity in 2005 and since then have provided a valuable contribution to the UNEP Mercury Programme and established a close cooperation with other international programs (i.e., GEO Task HE-09-02d / GEOSS) and conventions (UNECE-Task Force on Hemispheric Transport of Air Pollution). The UNEP F&T aims to improve the global understanding of international mercury emission sources, fate and transport and to encourage collaborative research activities on different aspects of atmospheric mercury cycling at local, hemispheric and global scales. This paper provides an overview of major recent and future activities carried out by the Mercury Air Transport and Fate Research Partnership Area in the framework of the UNEP Mercury Programme and the ongoing negotiation process for developing a global legally binding instrument on mercury.

Comparisons of simulated and observed Northern Hemisphere temperature variations during the past millennium – selected lessons learned and problems encountered

ABSTRACTComparison of simulated and reconstructed past climate variability within the last millennium provides an opportunity to aid the understanding and interpretation of palaeoclimate proxy data and to test hypotheses regarding external forcings, feedback mechanisms and internal climate variability under conditions close to those of the present day. Most such comparisons have been made at the Northern Hemispheric scale, of which a selection of recent results is briefly discussed here. Uncertainties in climate and forcing reconstructions, along with the simplified representations of the true climate system represented by climate models, limit our possibility to draw certain conclusions regarding the nature of forced and unforced climate variability. Additionally, hemispheric-scale temperature variations have been comparatively small, wherefore the last millennium is apparently not a particularly useful period for estimating climate sensitivity. Nevertheless, several investigators have concluded that Northern Hemispheric-scale decadal-mean temperatures in the last millennium show a significant influence from natural external forcing, where volcanic forcing is significantly detectable while solar forcing is less robustly detected. The amplitude of centennial-scale variations in solar forcing has been a subject for much debate, but current understanding of solar physics implies that these variations have been small – similar in magnitude to those within recent sunspot cycles – and thus they have not been a main driver of climate in the last millennium. This interpretation is supported by various comparisons between forced climate model simulations and temperature proxy data. Anthropogenic greenhouse gas and aerosol forcing has been detected by the end of Northern Hemispheric temperature reconstructions.This paper is part of a Thematic Cluster in honor of the late Professor Bert Bolin for his outstanding contributions to climate science.

Long-term changes in lower tropospheric baseline ozone concentrations at northern mid-latitudes

Abstract. Changes in baseline (here understood as representative of continental to hemispheric scales) tropospheric O3 concentrations that have occurred at northern mid-latitudes over the past six decades are quantified from available measurement records with the goal of providing benchmarks to which retrospective model calculations of the global O3 distribution can be compared. Eleven data sets (ten ground-based and one airborne) including six European (beginning in the 1950's and before), three North American (beginning in 1984) and two Asian (beginning in 1991) are analyzed. When the full time periods of the data records are considered a consistent picture emerges; O3 has increased at all sites in all seasons at approximately 1% yr−1 relative to the site's 2000 yr mixing ratio in each season. For perspective, this rate of increase sustained from 1950 to 2000 corresponds to an approximate doubling. There is little if any evidence for statistically significant differences in average rates of increase among the sites, regardless of varying length of data records. At most sites (most definitively at the European sites) the rate of increase has slowed over the last decade (possibly longer), to the extent that at present O3 is decreasing at some sites in some seasons, particularly in summer. The average rate of increase before 2000 shows significant seasonal differences (1.08 ± 0.09, 0.89 ± 0.10, 0.85 ± 0.11 and 1.21 ± 0.12% yr−1 in spring, summer, autumn and winter, respectively, over North America and Europe).

The role of declining Arctic sea ice in recent decreasing terrestrial Arctic snow depths

The dramatic decline in Arctic sea ice cover is anticipated to influence atmospheric temperatures and circulation patterns. These changes will affect the terrestrial climate beyond the boundary of the Arctic, consequently modulating terrestrial snow cover. Therefore, an improved understanding of the relationship between Arctic sea ice and snow depth over the terrestrial Arctic is warranted. We examined responses of snow depth to the declining Arctic sea ice extent in September, during the period of 1979–2006. The major reason for a focus on snow depth, rather than snow cover, is because its variability has a climatic memory that impacts hydrothermal processes during the following summer season. Analyses of combined data sets of satellite measurements of sea ice extent and snow depth, simulated by a land surface model (CHANGE), suggested that an anomalously larger snow depth over northeastern Siberia during autumn and winter was significantly correlated to the declining September Arctic sea ice extent, which has resulted in cooling temperatures, along with an increase in precipitation. Meanwhile, the reduction of Arctic sea ice has amplified warming temperatures in North America, which has readily offset the input of precipitation to snow cover, consequently further decreasing snow depth. However, a part of the Canadian Arctic recorded an increase in snow depth driven locally by the diminishing September Arctic sea ice extent. Decreasing snow depth at the hemispheric scale, outside the northernmost regions (i.e., northeastern Siberia and Canadian Arctic), indicated that Arctic amplification related to the diminishing Arctic sea ice has already impacted the terrestrial Arctic snow depth. The strong reduction in Arctic sea ice anticipated in the future also suggests a potential long-range impact on Arctic snow cover. Moreover, the snow depth during the early snow season tends to contribute to the warming of soil temperatures in the following summer, at least in the northernmost regions.

Hemispheric snow water equivalent: The need for a synergistic approach

Snow plays a crucial role in climatological and hydrological processes, and it is a key factor in modulating energy, water, and carbon budgets. The optically bright snow‐covered surface regulates the amount of solar radiation absorbed by the Earth, which influences regional energy budgets. Snow water equivalent (SWE), the amount of water stored within the snowpack, has wide‐ranging effects: playing a critical role in the management of water resources and hydropower production, influencing the soil temperature through thermally insulating properties, and affecting the ability of rangifers (i.e., caribou) to efficiently forage for food. These are some examples of the importance of estimating snow depth and SWE across regional and hemispheric scales.

Data-driven modeling of surface temperature anomaly and solar activity trends

A novel two-step modeling scheme is used to reconstruct and analyze surface temperature and solar activity data at global, hemispheric, and regional scales. First, the self-organizing map (SOM) technique is used to extend annual modern climate data from the century to millennial scale. The SOM component planes are used to identify and quantify strength of nonlinear relations among modern surface temperature anomalies (<150 years), tropical and extratropical teleconnections, and Palmer Drought Severity Indices (0–2000 years). Cross-validation of global sea and land surface temperature anomalies verifies that the SOM is an unbiased estimator with less uncertainty than the magnitude of anomalies. Second, the quantile modeling of SOM reconstructions reveal trends and periods in surface temperature anomaly and solar activity whose timing agrees with published studies. Temporal features in surface temperature anomalies, such as the Medieval Warm Period, Little Ice Age, and Modern Warming Period, appear at all spatial scales but whose magnitudes increase when moving from ocean to land, from global to regional scales, and from southern to northern regions. Some caveats that apply when interpreting these data are the high-frequency filtering of climate signals based on quantile model selection and increased uncertainty when paleoclimatic data are limited. Even so, all models find the rate and magnitude of Modern Warming Period anomalies to be greater than those during the Medieval Warm Period. Lastly, quantile trends among reconstructed equatorial Pacific temperature profiles support the recent assertion of two primary El Niño Southern Oscillation types. These results demonstrate the efficacy of this alternative modeling approach for reconstructing and interpreting scale-dependent climate variables.