Seasonal variations in pCO2 and its controlling factors in surface seawater of the northern East China Sea

Surface partial pressure of CO₂ (pCO₂), temperature, salinity, nutrients, and chlorophyll a were measured in the East China Sea (ECS; 31°30′–34°00′N to 124°00′–127°30′E) in August 2003 (summer), May 2004 (spring), October 2004 (early fall), and November 2005 (fall). The warm and saline Tsushima Warm Current was observed in the eastern part of the survey area during four cruises, and relatively low salinity waters due to outflow from the Changjiang (Yangtze River) were observed over the western part of the survey area. Surface pCO₂ ranged from 236 to 445 μatm in spring and summer, and from 326 to 517 μatm in fall. Large pCO₂ (values >400 μatm) occurred in the western part of the study area in spring and fall, and in the eastern part in summer. A positive linear correlation existed between surface pCO₂ and temperature in the eastern part of the study area, where the Tsushima Warm Current dominates; this correlation suggests that temperature is the major factor controlling surface pCO₂ distribution in that area. In the western part of the study area, however, the main controlling factor is different and seasonally complex. There is large transport in this region of Changjiang Diluted Water in summer, causing low salinity and low pCO₂ values. The relationship between surface pCO₂ and water stability suggests that the amount of mixing and/or upwelling of CO₂-rich water might be the important process controlling surface pCO₂ levels during spring and fall in this shallow region. Sea–air CO₂ flux, based on the application of a Wanninkhof [1992. Relationship between wind speed and gas exchange over the ocean. Journal of Geophysical Research 97, 7373–7382] formula for gas transfer velocity and a set of monthly averaged satellite wind data, were −5.04±1.59, −2.52±1.81, 1.71±2.87, and 0.39±0.18 mmol m⁻² d⁻¹ in spring, summer, early fall, and fall, respectively, in the northern ECS. The ocean in this study area is therefore a carbon sink in spring and summer, but a weak source or in equilibrium with the atmosphere in fall. If the winter flux value is assumed to have been the mean of autumnal and vernal values, then the northern ECS absorbs about 0.013 Pg C annually. That result suggests that the northern ECS is a net sink for atmospheric CO₂, a result consistent with previous studies.     

Integration of the nuclease protection assay with sandwich hybridization (NPA-SH) for sensitive detection of Heterocapsa triquetra

Microalgae are photosynthetic microorganisms that function as primary producers in aquatic ecosystems. Some species of microalgae undergo rapid growth and cause harmful blooms in marine ecosystems. Heterocapsa triquetra is one of the most common bloom-forming species in estuarine and coastal waters worldwide. Although this species does not produce toxins, unlike some other Heterocapsa species, the high density of its blooms can cause significant ecological damage. We developed a H. triquetra species-specific nuclease protection assay sandwich hybridization(NPA-SH) probe that targets the large subunit of ribosomal RNA(LSU r RNA). We tested probe specificity and sensitivity with five other dinoflagellates that also cause red tides. Our assay detected H.triquetra at a concentration of 1.5×104 cells/m L, more sensitive than required for a red-tide guidance warning by the Korea Ministry of Oceans and Fisheries in 2015(3.0×104 cells/m L). We also used the NPA-SH assay to monitor H. triquetra in the Tongyeong region of the southern sea area of Korea during 2014. This method could detect H.triquetra cells within 3 h. Our assay is useful for monitoring H. triquetra under field conditions.     

The impacts of climate change on local hydrology and low flow frequency in the Geum River Basin,Korea

The climate sensitive analysis of potential climate change on streamflow has been conducted using a hydrologic model to identify hydrologic variability associated with climate scenarios as a function of perturbed climatic variables (e.g. carbon dioxide, temperature, and precipitation). The interannual variation of water resources availability as well as low flow frequency driven by monsoonal time shifts have been investigated to evaluate the likelihood of droughts in a changing climate. The results show that the timing shift of the monsoon window associated with future climate scenarios clearly affect annual water yield change of ? 12 and ? 8% corresponding to 1‐month earlier and 1‐month later monsoon windows, respectively. Also, a more severe low flow condition has been predicted at 0·03 m³/s as opposed to the historic 7Q10 flow of 1·54 m³/s given at extreme climate scenarios. Copyright © 2011 John Wiley & Sons, Ltd.     

A new scenario framework for climate change research: background,process, and future directions

The scientific community is developing new global, regional, and sectoral scenarios to facilitate interdisciplinary research and assessment to explore the range of possible future climates and related physical changes that could pose risks to human and natural systems; how these changes could interact with social, economic, and environmental development pathways; the degree to which mitigation and adaptation policies can avoid and reduce risks; the costs and benefits of various policy mixes; and the relationship of future climate change adaptation and mitigation policy responses with sustainable development. This paper provides the background to and process of developing the conceptual framework for these scenarios, as described in the three subsequent papers in this Special Issue (Van Vuuren et al., 2013; O’Neill et al., 2013; Kriegler et al., Submitted for publication in this special issue). The paper also discusses research needs to further develop, apply, and revise this framework in an iterative and open-ended process. A key goal of the framework design and its future development is to facilitate the collaboration of climate change researchers from a broad range of perspectives and disciplines to develop policy- and decision-relevant scenarios and explore the challenges and opportunities human and natural systems could face with additional climate change.     

The role of technology for achieving climate policy objectives: overview of the EMF 27 study on global technology and climate policy strategies

This article presents the synthesis of results from the Stanford Energy Modeling Forum Study 27, an inter-comparison of 18 energy-economy and integrated assessment models. The study investigated the importance of individual mitigation options such as energy intensity improvements, carbon capture and storage (CCS), nuclear power, solar and wind power and bioenergy for climate mitigation. Limiting the atmospheric greenhouse gas concentration to 450 or 550 ppm CO₂ equivalent by 2100 would require a decarbonization of the global energy system in the 21^st century. Robust characteristics of the energy transformation are increased energy intensity improvements and the electrification of energy end use coupled with a fast decarbonization of the electricity sector. Non-electric energy end use is hardest to decarbonize, particularly in the transport sector. Technology is a key element of climate mitigation. Versatile technologies such as CCS and bioenergy are found to be most important, due in part to their combined ability to produce negative emissions. The importance of individual low-carbon electricity technologies is more limited due to the many alternatives in the sector. The scale of the energy transformation is larger for the 450 ppm than for the 550 ppm CO₂e target. As a result, the achievability and the costs of the 450 ppm target are more sensitive to variations in technology availability.     

The representative concentration pathways: an overview

This paper summarizes the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new pathways developed for the climate modeling community as a basis for long-term and near-term modeling experiments. The four RCPs together span the range of year 2100 radiative forcing values found in the open literature, i.e. from 2.6 to 8.5 W/m². The RCPs are the product of an innovative collaboration between integrated assessment modelers, climate modelers, terrestrial ecosystem modelers and emission inventory experts. The resulting product forms a comprehensive data set with high spatial and sectoral resolutions for the period extending to 2100. Land use and emissions of air pollutants and greenhouse gases are reported mostly at a 0.5?×?0.5 degree spatial resolution, with air pollutants also provided per sector (for well-mixed gases, a coarser resolution is used). The underlying integrated assessment model outputs for land use, atmospheric emissions and concentration data were harmonized across models and scenarios to ensure consistency with historical observations while preserving individual scenario trends. For most variables, the RCPs cover a wide range of the existing literature. The RCPs are supplemented with extensions (Extended Concentration Pathways, ECPs), which allow climate modeling experiments through the year 2300. The RCPs are an important development in climate research and provide a potential foundation for further research and assessment, including emissions mitigation and impact analysis.     

Deficiencies and possibilities for long-lead coupled climate prediction of the Western North Pacific-East Asian summer monsoon

Long-lead prediction of waxing and waning of the Western North Pacific (WNP)-East Asian (EA) summer monsoon (WNP-EASM) precipitation is a major challenge in seasonal time-scale climate prediction. In this study, deficiencies and potential for predicting the WNP-EASM precipitation and circulation one or two seasons ahead were examined using retrospective forecast data for the 26-year period of 1981–2006 from two operational couple models which are the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFS) and the Bureau of Meteorology Research Center (BMRC) Predictive Ocean–Atmosphere Model for Australia (POAMA). While both coupled models have difficulty in predicting summer mean precipitation anomalies over the region of interest, even for a 0-month lead forecast, they are capable of predicting zonal wind anomalies at 850 hPa several months ahead and, consequently, satisfactorily predict summer monsoon circulation indices for the EA region (EASMI) and for the WNP region (WNPSMI). It should be noted that the two models’ multi-model ensemble (MME) reaches 0.40 of the correlation skill for the EASMI with a January initial condition and 0.75 for the WNPSMI with a February initial condition. Further analysis indicates that prediction reliability of the EASMI is related not only to the preceding El Niño and Southern Oscillation (ENSO) but also to simultaneous local SST variability. On other hand, better prediction of the WNPSMI is accompanied by a more realistic simulation of lead–lag relationship between the index and ENSO. It should also be noted that current coupled models have difficulty in capturing the interannual variability component of the WNP-EASM system which is not correlated with typical ENSO variability. To improve the long-lead seasonal prediction of the WNP-EASM precipitation, a statistical postprocessing was developed based on the multiple linear regression method. The method utilizes the MME prediction of the EASMI and WNPSMI as predictors. It is shown that the statistical postprocessing is able to improve forecast skill for the summer mean precipitation over most of the WNP-EASM region at all forecast leads. It is noteworthy that the MME prediction, after applying statistical postprocessing, shows the best anomaly pattern correlation skill for the EASM precipitation at a 4-month lead (February initial condition) and for the WNPSM precipitation at a 5-month lead (January initial condition), indicating its potential for improving long-lead prediction of the monsoon precipitation.     

Uncertainty analysis for the integration of seismic and controlled source electro‐magnetic data

We study the appraisal problem for the joint inversion of seismic and controlled source electro‐magnetic (CSEM) data and utilize rock‐physics models to integrate these two disparate data sets. The appraisal problem is solved by adopting a Bayesian model and we incorporate four representative sources of uncertainty. These are uncertainties in 1) seismic wave velocity, 2) electric conductivity, 3) seismic data and 4) CSEM data. The uncertainties in porosity and water saturation are quantified by a posterior random sampling in the model space of porosity and water saturation in a marine one‐dimensional structure. We study the relative contributions from the four individual sources of uncertainty by performing several statistical experiments. The uncertainties in the seismic wave velocity and electric conductivity play a more significant role on the variation of posterior uncertainty than do the seismic and CSEM data noise. The numerical simulations also show that the uncertainty in porosity is most affected by the uncertainty in the seismic wave velocity and that the uncertainty in water saturation is most influenced by the uncertainty in electric conductivity. The framework of the uncertainty analysis presented in this study can be utilized to effectively reduce the uncertainty of the porosity and water saturation derived from the integration of seismic and CSEM data.     

Field observations from the Aquila, Italy earthquake of April 6, 2009

On April 6, 2009 an earthquake of magnitude 6.2 (M_w) struck the Abbruzzo region of Italy causing widespread damage to buildings in the city of L??Aquila and surrounding areas. This paper summarizes field observations made by the Earthquake Engineering Field Investigation Team (EEFIT) after the event. The paper presents an overview of seismological and geotechnical aspects of the earthquake as well as a summary of the observed damage to buildings and infrastructure. A brief overview of the earthquake casualties is also reported.