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There has been widespread adoption of downscaled products amongst practitioners and stakeholders to ascertain risk from climate hazards at the local scale (e.g., ∼ 5 km resolution). Such products must nevertheless be consistent with physical laws to be credible and of value to users. Here we evaluate statistically and dynamically downscaled products by examining local co-evolution of downscaled temperature and precipitation during convective and frontal precipitation events (two mechanisms testable with just temperature and precipitation). We find that two widely used statistical downscaling techniques (Localized Constructed Analogs version 2, LOCA2, and Seasonal Trends and Analysis of Residuals Empirical Statistical Downscaling Model, STAR-ESDM) generally preserve expected co-variances during convective precipitation events over the historical and future projected intervals as compared to European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA5) and two observation-based data products (Livneh and nClimGrid-Daily). However, both techniques dampen future intensification of frontal precipitation that is otherwise robustly captured in global climate models (i.e., prior to downscaling) and with process-based dynamical downscaling across five different regional climate models. In the case of LOCA2, this leads to appreciable underestimation of future frontal precipitation event intensity. This study is one of the first to quantify a likely ramification of the stationarity assumption underlying statistical downscaling methods and identify a phenomenon where projections of future change diverge depending on data production method employed. Finally, our work proposes expected co-variances during convective and frontal precipitation as useful evaluation diagnostics that can be universally applied to a wide range of statistically downscaled products. [ABSTRACT FROM AUTHOR]

Enhanced rock weathering (ERW) on croplands has emerged as an economically and ecologically promising negative emissions technology. However, estimated total carbon sequestration potential from ERW on croplands and its potential sensitivity to climate conditions requires further understanding. Here we combine 1‐D reactive transport modeling with climate model experiments to simulate ERW on ∼1,000 agricultural sites globally. Applying a fixed rate of 10 tons of basalt dust per hectare on these sites sequesters 64 gigatons of CO2 over a 75‐year period; when extrapolated to all agricultural land, ERW sequesters 217 gigatons of CO2 over the same time interval. However, we find that a significant fraction of applied basalt does not weather even on a multidecadal timescale, indicating the need to optimize application strategies for cost effectiveness. We find that ERW becomes modestly more effective with global warming and predict that the payback period for a given ERW deployment is significantly shorter in hot and humid environments currently coinciding with relatively low per‐capita incomes. These results provide strong impetus for investment in agricultural reform in developing economies and highlight an additional potential co‐benefit of ERW. Plain Language Summary: Enhanced rock weathering (ERW) on croplands is a promising negative emissions concept that accelerates natural weathering by amending soils with crushed rock. Our simulations of ERW with a fixed rate of 10 tons of basalt dust per hectare on all global croplands suggest ERW can sequester >200 gigatons of CO2 over a 75‐year period. This suggests that cost and logistical concerns, rather than weathering potential, are likely to be the key limiting factors for large‐scale deployment of enhanced weathering. Notably, ERW is resilient to global climate change and becomes more effective with global warming. ERW is moreover far more efficient in hot and humid environments currently coinciding with relatively low per‐capita gross domestic product economies. Our study provides strong support for the assertion that ERW represents a resilient carbon capture strategy that is non‐competitive for arable land and can foster CO2 removal at the gigaton scale. Key Points: Enhanced rock weathering (ERW) with fixed annual application rates of 10 tons of basalt dust per hectare on 1,000 global cropland sites sequesters 64 gigatons of CO2 over 2006–2080Extrapolated to all croplands, ERW with a fixed application rate of 10 tons of basalt dust per hectare sequesters 215 gigatons of CO2 over 2006–2080ERW is resilient to global climate change but is much more efficient over hot and humid environments [ABSTRACT FROM AUTHOR]

We illustrate efficient methods to estimate future projected average return intervals (ARIs) of flood depths in coastal regions from storm-tide data and sea-level rise (SLR) projections. A flood-water path-finding algorithm is applied to digital elevation models (DEMs) in coastal regions to determine possible flood depths at interior points, given storm-tide levels at ARIs and local SLR with uncertainty on the coast. We show that the distribution of projected ARIs of a historical baseline flood-depth is truncated log-normal in the Gumbel extreme-value approximation, and we provide analytic expressions for the means. With this approximation, projected change in flood damage over a range of ARIs can be estimated by analysis at any single ARI. Compared to flood-depth distributions, ARI distributions are less directly related to flood damage, but they have the advantage of relative insensitivity to uncertainties in DEMs and other granular details of flood-risk modeling. We illustrate with applications to Miami, Florida, and coastal North Carolina using two different DEMs. [ABSTRACT FROM AUTHOR]

Prior studies that argue external forcings drive Atlantic Multidecadal Variability (AMV) use linear detrending to remove the global warming trend from North Atlantic sea surface temperatures (SSTs). The linear detrending method, however, aliases residual nonlinear, global‐scale warming, affecting the interpretation of results. Here we revisit the role of external forcing in AMV using large climate model ensembles, examining the influences of greenhouse gases (GHGs) and industrial aerosols—the two dominant 20th‐century external forcing agents—on North Atlantic SSTs separately from their respective global response. Our approach shows that GHGs have little to no influence unique to the North Atlantic, while industrial aerosols exert only modest influences as part of a broader loading over the Northern Hemisphere. We demonstrate that a prominent role for external forcings on AMV is an artifact of the linear detrending method that disappears when their global responses common to the World Ocean are correctly accounted for. Plain Language Summary: The origin of Atlantic Multidecadal Variability (AMV) is widely debated, with discussions focused on whether it is an internal mode of the coupled climate system or a response to external radiative forcings. Most studies that identify a dominant role for external forcings in driving AMV apply linear detrending to remove the global warming trend from North Atlantic SSTs. This is problematic because the linear detrending method does not sufficiently remove the global warming signal. In this study, we re‐examine the role of external forcing in 20th‐century AMV, correctly accounting for global forcing influences common to the entire World Ocean. Separate analysis of the roles of greenhouse gases (GHGs) and industrial aerosols on AMV, independent of their respective planetary influence, shows that GHGs have little to no influence unique to the North Atlantic, while industrial aerosols exert only modest influences as part of a broader impact on the Northern Hemisphere oceans. Our results suggest that linear signal separation methods that do not fully isolate the influences of global forcing on North Atlantic temperatures incorrectly inflate the role played by external forcing. When these approaches are avoided, our results indicate that external forcing has little influence on AMV compared to variability internal to the climate system. Key Points: Linearly detrending North Atlantic sea surface temperatures conflate variability unique to the Atlantic with aliased residual, nonlinear, global warmingThe role of external forcing on Atlantic Multidecadal Variability (AMV) is greatly diminished when global forcing signals are sufficiently removedRoles for historical forcing on AMV previously identified with the linear detrending method are likely an unphysical artifact [ABSTRACT FROM AUTHOR]

The largest sea surface temperature (SST) anomalies associated with Atlantic Multidecadal Variability (AMV) occur over the Atlantic subpolar gyre, yet it is the tropical Atlantic from where the global impacts of AMV originate. Processes that communicate SST change from the subpolar Atlantic gyre to the tropical North Atlantic thus comprise a crucial mechanism of AMV. Here we use idealized model experiments to show that such communication is accomplished by an "atmospheric bridge." Our results demonstrate an unexpected asymmetry: the atmosphere is effective in communicating cold subpolar SSTs to the north tropical Atlantic, via an immediate extratropical atmospheric circulation change that invokes slower wind‐driven evaporative cooling along the Eastern Atlantic Basin and into the tropics. Warm subpolar SST anomalies do not elicit a robust tropical Atlantic response. Our results highlight a key dynamical feature of AMV for which warm and cold phases are not opposites. Plain Language Summary: To investigators of Atlantic Multidecadal Variability (AMV), one outstanding conundrum is the discrepancy between where the largest AMV changes occur (subpolar North Atlantic) and where the remote impacts of AMV originate (tropical North Atlantic). Processes that communicate sea surface temperature (SST) changes from the subpolar gyre region to the tropical North Atlantic are a potentially crucial but poorly understood aspect of AMV. Here, using idealized model experiments, we investigate the idea that such communication is accomplished by an "atmospheric bridge"—a fast, basin‐wide atmospheric response to subpolar gyre SST anomalies that produces a tropical SST change. Our results demonstrate an unexpected, but robust asymmetry: The atmosphere is effective in communicating, via a fast circulation change that invokes wind‐driven evaporative cooling along the Eastern Basin, only cold SST anomalies from the Atlantic subpolar gyre to the tropical North Atlantic. In contrast, imposed warm subpolar SST anomalies do not elicit a tropical Atlantic response. Our results highlight a key dynamical feature of AMV for which warm and cold phases are not opposites. Key Points: A fast, basin‐wide atmospheric response to Atlantic subpolar gyre sea surface temperature (SST) anomalies connects the subpolar and tropical Atlantic regionsThis "atmospheric bridge" communicates, via wind‐driven evaporative cooling, only cold subpolar Atlantic SSTs to the tropical AtlanticThe atmospheric bridge does not effectively communicate warm subpolar Atlantic SSTs, highlighting an important asymmetry of AMV [ABSTRACT FROM AUTHOR]

We examine oceanic drivers of widespread droughts over the contiguous United States (herein pan‐CONUS droughts) during the Common Era in what is one of the first analyses of the new Paleo Hydrodynamics Data Assimilation (PHYDA) product. The canonical understanding of oceanic influences on North American hydroclimate suggests that pan‐CONUS droughts are forced by a contemporaneous cold tropical Pacific Ocean and a warm tropical Atlantic Ocean. We test this hypothesis using the paleoclimate record. Composite analyses find a robust association between pan‐CONUS drought events and cold tropical Pacific conditions, but not with warm Atlantic conditions. Similarly, a self‐organizing map analysis shows that pan‐CONUS drought years are most commonly associated with a global sea surface temperature pattern displaying strong La Niña and cold Atlantic Multidecadal Oscillation (AMO) conditions. Our results confirm previous model‐based findings for the instrumental period and show that cold tropical Pacific Ocean conditions are the principal driver of pan‐CONUS droughts on annual timescales. Plain Language Summary: Widespread summer droughts across the contiguous United States (pan‐CONUS droughts) pose unique challenges because of their potential to strain multiple water resources simultaneously, and the financial damages from these droughts are significant. For example, pan‐CONUS droughts in 1988 and 2012 cost an estimated $40 and $30 billion, respectively. We provide a millennium‐length perspective on the causes of these droughts using a new paleo reconstruction product that merges climate model information with multiple climate proxies including tree rings, ice cores, and corals. We characterize pan‐CONUS droughts from 850 to 1850 CE and demonstrate how ocean variability has helped cause these events. We find that La Niña events in the tropical Pacific are the principal oceanic influence on these droughts, while variability in the Atlantic has not played a significant role. These findings are at odds with previous work that has estimated a role for the Atlantic in causing pan‐CONUS droughts but support conclusions from a more recent model‐based study of the causes of pan‐CONUS droughts over the instrumental record. Our findings are important for predictions of pan‐CONUS droughts and for determining how the occurrence of these droughts may change in the future due to increases in greenhouse gas emissions. Key Points: Widespread summer droughts in the contiguous United States have been endemic over much of the Common Era based on a new paleo data assimilation productLa Niñas are the principal driver of these widespread droughts, while the Atlantic is shown to have played a passive roleThe oceanic drivers of these droughts over the paleo record is consistent with previous model‐based findings over the instrumental record [ABSTRACT FROM AUTHOR]

The contributions of oceanic and atmospheric variability to spatially widespread summer droughts in the contiguous United States (hereafter, pan‐CONUS droughts) are investigated using 16‐member ensembles of the Community Climate Model version 3 (CCM3) forced with observed sea surface temperatures (SSTs) from 1856–2012. The employed SST forcing fields are either (i) global or restricted to the (ii) tropical Pacific or (iii) tropical Atlantic to isolate the impacts of these two ocean regions on pan‐CONUS droughts. Model results show that SST forcing of pan‐CONUS droughts originates almost entirely from the tropical Pacific because of atmospheric highs from the northern Pacific to eastern North America established by La Niña conditions, with little contribution from the tropical Atlantic. Notably, in all three model configurations, internal atmospheric variability influences pan‐CONUS drought occurrence by as much or more than the ocean forcing and can alone cause pan‐CONUS droughts by establishing a dominant high centered over the U.S. montane west. Similar results are found for the Community Atmosphere Model version 5 (CAM5). Model results are compared to the observational record, which supports model‐inferred contributions to pan‐CONUS droughts from La Niñas and internal atmospheric variability. While there may be an additional association with warm Atlantic SSTs in the observational record, this association is ambiguous due to the limited number of observed pan‐CONUS droughts. The ambiguity thus opens the possibility that the observational results are limited by sampling over the twentieth century and not at odds with the suggested dominance of Pacific Ocean forcing in the model ensembles. Key Points: Models forced with observed sea surface temperatures replicate spatially widespread summer droughts over the contiguous United StatesVariability in the tropical Pacific explains almost all the ocean forcing of these droughts in the models; the Atlantic plays an ambiguous roleContributions to these droughts from internal atmospheric variability are roughly equal to or greater than the collective ocean forcing [ABSTRACT FROM AUTHOR]

The tree-ring-based North American Drought Atlas (NADA), Monsoon Asia Drought Atlas (MADA), and Old World Drought Atlas (OWDA) collectively yield a near-hemispheric gridded reconstruction of hydroclimate variability over the last millennium. To test the robustness of the large-scale representation of hydroclimate variability across the drought atlases, the joint expression of seasonal climate variability and teleconnections in the NADA, MADA, and OWDA are compared against two global, observation-based PDSI products. Predominantly positive (negative) correlations are determined between seasonal precipitation (surface air temperature) and collocated tree-ring-based PDSI, with average Pearson's correlation coefficients increasing in magnitude from boreal winter to summer. For precipitation, these correlations tend to be stronger in the boreal winter and summer when calculated for the observed PDSI record, while remaining similar for temperature. Notwithstanding these differences, the drought atlases robustly express teleconnection patterns associated with El Niño-Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), the Pacific decadal oscillation (PDO), and the Atlantic multidecadal oscillation (AMO). These expressions exist in the drought atlas estimates of boreal summer PDSI despite the fact that these modes of climate variability are dominant in boreal winter, with the exception of the AMO. ENSO and NAO teleconnection patterns in the drought atlases are particularly consistent with their well-known dominant expressions in boreal winter and over the OWDA domain, respectively. Collectively, the findings herein confirm that the joint Northern Hemisphere drought atlases robustly reflect large-scale patterns of hydroclimate variability on seasonal to multidecadal time scales over the twentieth century and are likely to provide similarly robust estimates of hydroclimate variability prior to the existence of widespread instrumental data. [ABSTRACT FROM AUTHOR]

SUMMARY We investigated the seasonal abundance of the dinoflagellate Heterocapsa triquetra (Ehrenberg) F. Stein, as well as the relevant in situ environmental factors, in brackish Lake Shihwa, Korea. We also examined the growth rates and morphological characteristics of the species in laboratory cultures. In the field, the population densities of H. triquetra remained at low levels from late spring to early summer, and then completely disappeared from August to November 2007. Interestingly, a dense bloom of H. triquetra appeared below the ice surface on 17 January 2008; identities of the cells were confirmed by rDNA sequence comparisons. The second peak reached a density of 672 × 103 cells L−1 on 28 March 2008, at a water temperature of 9.1°C. Laboratory experiments showed that growth rates of H. triquetra increased with incremental temperature increases within the range of 10 and 20°C. The highest growth rate reached by H. triquetra was 0.62 d−1 at 20°C with a salinity of 30. Above 25°C, the dinoflagellate was unable to grow between salinities of 10 and 15, and reached only relatively low growth rates (<0.12 d−1) under other salinity conditions. However, under continuous cultures at 5°C and 8°C, H. triquetra cells retained its growth capability for more than 12 days, implying that H. triquetra can survive and grows even at very low temperatures. The equivalent spherical diameter (ESD) of H. triquetra did not change markedly between 10 and 25°C, but the equivalent spherical diameter was significantly different at 5°C. The cell volume buildup of H. triquetra at low temperatures is one of the important survival strategies to overcome the harsh environmental conditions. These characteristics make H. triquetra a consistently dominant dinoflagellate in Lake Shihwa during the cold winter season. [ABSTRACT FROM AUTHOR]

The article presents a study concerning the dual features functional support vector machine for the early detection of faulty batteries in manufacturing processes. It outlines the use of the existing original performance degradation profiles, but the approach is not effective in detecting faulty batteries which prompted the proposal of dual features functional support vector machine measure. It highlights the application of the modified floating search algorithm for the repeated feature selection, as well as the sampling plan for time-varying classification errors to determine the optimal number of test cycles. It illustrates the improved performance of the proposed approach compared to the existing method wherein the process can be applied to a wide range of manufacturing processes.