As table 2 but for precipitation responses to the surface temperature changes (d<em>P</em>/d<em>T</em>)

<p><b>Table 3.</b>  As table <a href="http://iopscience.iop.org/1748-9326/8/3/034002/article#erl470150t2" target="_blank">2</a> but for precipitation responses to the surface temperature changes (d<em>P</em>/d<em>T</em>). </p> <p><strong>Abstract</strong></p> <p>Global warming is expected to enhance fluxes of fresh water between the surface and atmosphere, causing wet regions to become wetter and dry regions drier, with serious implications for water resource management. Defining the wet and dry regions as the upper 30% and lower 70% of the precipitation totals across the tropics (30° S–30° N) each month we combine observations and climate model simulations to understand changes in the wet and dry regions over the period 1850–2100. Observed decreases in precipitation over dry tropical land (1950–2010) are also simulated by coupled atmosphere–ocean climate models (−0.3%/decade) with trends projected to continue into the 21st century. Discrepancies between observations and simulations over wet land regions since 1950 exist, relating to decadal fluctuations in El Niño southern oscillation, the timing of which is not represented by the coupled simulations. When atmosphere-only simulations are instead driven by observed sea surface temperature they are able to adequately represent this variability over land. Global distributions of precipitation trends are dominated by spatial changes in atmospheric circulation. However, the tendency for already wet regions to become wetter (precipitation increases with warming by 3% K⁻¹ over wet tropical oceans) and the driest regions drier (precipitation decreases of −2% K⁻¹ over dry tropical land regions) emerges over the 21st century in response to the substantial surface warming.</p

Precipitation trend for different data sets over various time periods

<p><b>Table 2.</b>  Precipitation trend for different data sets over various time periods. Statistically significant values at the 95% confidence level are marked bold. Δ<em>m</em> denotes the 95% confidence range. Trends from composite model runs are calculated from ensemble means. </p> <p><strong>Abstract</strong></p> <p>Global warming is expected to enhance fluxes of fresh water between the surface and atmosphere, causing wet regions to become wetter and dry regions drier, with serious implications for water resource management. Defining the wet and dry regions as the upper 30% and lower 70% of the precipitation totals across the tropics (30° S–30° N) each month we combine observations and climate model simulations to understand changes in the wet and dry regions over the period 1850–2100. Observed decreases in precipitation over dry tropical land (1950–2010) are also simulated by coupled atmosphere–ocean climate models (−0.3%/decade) with trends projected to continue into the 21st century. Discrepancies between observations and simulations over wet land regions since 1950 exist, relating to decadal fluctuations in El Niño southern oscillation, the timing of which is not represented by the coupled simulations. When atmosphere-only simulations are instead driven by observed sea surface temperature they are able to adequately represent this variability over land. Global distributions of precipitation trends are dominated by spatial changes in atmospheric circulation. However, the tendency for already wet regions to become wetter (precipitation increases with warming by 3% K⁻¹ over wet tropical oceans) and the driest regions drier (precipitation decreases of −2% K⁻¹ over dry tropical land regions) emerges over the 21st century in response to the substantial surface warming.</p

Deseasonalized anomaly time series of temperature ((a), (b)) and precipitation minus evaporation (<em>P</em> − <em>E</em>) changes over the tropical oceans and the tropical land for ((c), (d)) wet and ((e), (f)) dry regions

<p><strong>Figure 1.</strong> Deseasonalized anomaly time series of temperature ((a), (b)) and precipitation minus evaporation (<em>P</em> − <em>E</em>) changes over the tropical oceans and the tropical land for ((c), (d)) wet and ((e), (f)) dry regions. The wet and dry regions are defined as the 30% highest and 70% lowest <em>P</em> − <em>E</em> grid points each month. Data are from the CMIP5 historical and RCP 4.5 simulations (1850–2100) and the AMIP simulations (1979–2008). Anomalies are calculated with respect to the 1860–1950 period for CMIP5 historical data, 1961–1990 for HadCRUT4 and 1988–2005 for AMIP5 data sets; HadCRUT4 and AMIP anomalies are adjusted to agree with the CMIP5 ensemble mean over the period 1988–2005. All lines are 48 month running means. The shaded area is the ensemble mean ± 1 standard deviation.</p> <p><strong>Abstract</strong></p> <p>Global warming is expected to enhance fluxes of fresh water between the surface and atmosphere, causing wet regions to become wetter and dry regions drier, with serious implications for water resource management. Defining the wet and dry regions as the upper 30% and lower 70% of the precipitation totals across the tropics (30° S–30° N) each month we combine observations and climate model simulations to understand changes in the wet and dry regions over the period 1850–2100. Observed decreases in precipitation over dry tropical land (1950–2010) are also simulated by coupled atmosphere–ocean climate models (−0.3%/decade) with trends projected to continue into the 21st century. Discrepancies between observations and simulations over wet land regions since 1950 exist, relating to decadal fluctuations in El Niño southern oscillation, the timing of which is not represented by the coupled simulations. When atmosphere-only simulations are instead driven by observed sea surface temperature they are able to adequately represent this variability over land. Global distributions of precipitation trends are dominated by spatial changes in atmospheric circulation. However, the tendency for already wet regions to become wetter (precipitation increases with warming by 3% K⁻¹ over wet tropical oceans) and the driest regions drier (precipitation decreases of −2% K⁻¹ over dry tropical land regions) emerges over the 21st century in response to the substantial surface warming.</p

Spatial structure of precipitation anomaly trend (left column) and trend difference relating to changes in precipitation intensity distribution (right column) from ((a), (e)) GPCP, ((b), (f)) AMIP5, ((c), (g)) CMIP historical and ((d), (h)) RCP 4.5 data sets

<p><strong>Figure 4.</strong> Spatial structure of precipitation anomaly trend (left column) and trend difference relating to changes in precipitation intensity distribution (right column) from ((a), (e)) GPCP, ((b), (f)) AMIP5, ((c), (g)) CMIP historical and ((d), (h)) RCP 4.5 data sets. The dry tropical oceans are marked with black dots and the dry tropical land with magenta dots (defined as the 70% lowest <em>P</em> grid points for the tropical oceans and the tropical land respectively using the 1988–2005 mean). Trends (%/decade) are calculated over 1988–2008 for GPCP and AMIP5 data sets, 1979–2005 for CMIP5 historical data and 2006–2055 for RCP 4.5 data set. Please note the non-linear colour bars.</p> <p><strong>Abstract</strong></p> <p>Global warming is expected to enhance fluxes of fresh water between the surface and atmosphere, causing wet regions to become wetter and dry regions drier, with serious implications for water resource management. Defining the wet and dry regions as the upper 30% and lower 70% of the precipitation totals across the tropics (30° S–30° N) each month we combine observations and climate model simulations to understand changes in the wet and dry regions over the period 1850–2100. Observed decreases in precipitation over dry tropical land (1950–2010) are also simulated by coupled atmosphere–ocean climate models (−0.3%/decade) with trends projected to continue into the 21st century. Discrepancies between observations and simulations over wet land regions since 1950 exist, relating to decadal fluctuations in El Niño southern oscillation, the timing of which is not represented by the coupled simulations. When atmosphere-only simulations are instead driven by observed sea surface temperature they are able to adequately represent this variability over land. Global distributions of precipitation trends are dominated by spatial changes in atmospheric circulation. However, the tendency for already wet regions to become wetter (precipitation increases with warming by 3% K⁻¹ over wet tropical oceans) and the driest regions drier (precipitation decreases of −2% K⁻¹ over dry tropical land regions) emerges over the 21st century in response to the substantial surface warming.</p

Time series of precipitation anomalies over the tropical oceans and land; ((a), (b)) over the wet tropical oceans and land; ((c), (d)) over the dry tropical oceans and land

<p><strong>Figure 2.</strong> Time series of precipitation anomalies over the tropical oceans and land; ((a), (b)) over the wet tropical oceans and land; ((c), (d)) over the dry tropical oceans and land. The reference period for CMIP5 historical and RCP 4.5 model simulations are from 1860 to 1950 and from 1988 to 2005 for GPCP and GPCC. The GPCP data prior to the microwave era (1988) over the tropical oceans are not plotted. GPCP and GPCC anomalies are adjusted to agree with the CMIP5 ensemble mean over the period 1988–2005. All lines are 48 month running means. The shaded area is the ensemble mean ± 1 standard deviation. The wet region is defined as the 30% highest <em>P</em> grid points and the dry region the 70% lowest <em>P</em> grid points each month.</p> <p><strong>Abstract</strong></p> <p>Global warming is expected to enhance fluxes of fresh water between the surface and atmosphere, causing wet regions to become wetter and dry regions drier, with serious implications for water resource management. Defining the wet and dry regions as the upper 30% and lower 70% of the precipitation totals across the tropics (30° S–30° N) each month we combine observations and climate model simulations to understand changes in the wet and dry regions over the period 1850–2100. Observed decreases in precipitation over dry tropical land (1950–2010) are also simulated by coupled atmosphere–ocean climate models (−0.3%/decade) with trends projected to continue into the 21st century. Discrepancies between observations and simulations over wet land regions since 1950 exist, relating to decadal fluctuations in El Niño southern oscillation, the timing of which is not represented by the coupled simulations. When atmosphere-only simulations are instead driven by observed sea surface temperature they are able to adequately represent this variability over land. Global distributions of precipitation trends are dominated by spatial changes in atmospheric circulation. However, the tendency for already wet regions to become wetter (precipitation increases with warming by 3% K⁻¹ over wet tropical oceans) and the driest regions drier (precipitation decreases of −2% K⁻¹ over dry tropical land regions) emerges over the 21st century in response to the substantial surface warming.</p

Observed and simulated data sets and their properties

<p><b>Table 1.</b>  Observed and simulated data sets and their properties. Ticks indicate the data set is used in the corresponding analysis. </p> <p><strong>Abstract</strong></p> <p>Global warming is expected to enhance fluxes of fresh water between the surface and atmosphere, causing wet regions to become wetter and dry regions drier, with serious implications for water resource management. Defining the wet and dry regions as the upper 30% and lower 70% of the precipitation totals across the tropics (30° S–30° N) each month we combine observations and climate model simulations to understand changes in the wet and dry regions over the period 1850–2100. Observed decreases in precipitation over dry tropical land (1950–2010) are also simulated by coupled atmosphere–ocean climate models (−0.3%/decade) with trends projected to continue into the 21st century. Discrepancies between observations and simulations over wet land regions since 1950 exist, relating to decadal fluctuations in El Niño southern oscillation, the timing of which is not represented by the coupled simulations. When atmosphere-only simulations are instead driven by observed sea surface temperature they are able to adequately represent this variability over land. Global distributions of precipitation trends are dominated by spatial changes in atmospheric circulation. However, the tendency for already wet regions to become wetter (precipitation increases with warming by 3% K⁻¹ over wet tropical oceans) and the driest regions drier (precipitation decreases of −2% K⁻¹ over dry tropical land regions) emerges over the 21st century in response to the substantial surface warming.</p

Hydrologic and Biochemical Processes Controlling Chromium Immobilization in a Low-Permeability Groundwater Zone

Experiments and modeling were performed to investigate the coupled hydrologic and biochemical processes that control chromium (Cr) immobilization in a low-permeability groundwater zone. Bench-top flow cells were packed with a water-saturated high-permeability zone (HPZ) overlying a low-permeability zone (LPZ). Cr(VI) was initially flushed into the LPZ to establish a reservoir of this contaminant. Next, the electron donor acetate and the bacterium Geobacter sulfurreducens were flushed into the HPZ; they mixed with Cr(VI) in the LPZ and promoted its reduction. Experimental depth profiles show that approximately 80% of Cr(VI) introduced to the flow cell was immobilized as Cr(III) over 180 h within a small region on either side of the HPZ–LPZ interface. Groundwater flow and reactive transport in the flow cell were simulated using MODFLOW and RT3D, respectively, with dual-Monod kinetics defined in the custom reaction module of RT3D. Modeling results adequately matched experimental data and were extended to simulate Cr(VI) fate in a numerical flow cell with the same dimensions but with the LPZ replaced by a diffusion-controlled lower permeability clay matrix. For this scenario, approximately 99% of Cr(VI) in the LPZ could eventually be immobilized as Cr(III); this primarily occurred in the LPZ and mitigated Cr(VI) back diffusion to the HPZ. Overall, results from this work support acetate amendment to HPZs as an effective strategy to trap Cr(III) in LPZs and mitigate back diffusion of Cr(VI) into adjacent HPZs of a groundwater aquifer

Contribution of Ammonium-Induced Nitrifier Denitrification to N₂O in Paddy Fields

Paddy fields are one of the most important sources of nitrous oxide (N2O), but biogeochemical N2O production mechanisms in the soil profile remain unclear. Our study used incubation, dual-isotope (15N–18O) labeling methods, and molecular techniques to elucidate N2O production characteristics and mechanisms in the soil profile (0–60 cm) during summer fallow, rice cropping, and winter fallow periods. The results pointed out that biotic processes dominated N2O production (72.2–100%) and N2O from the tillage layer accounted for 91.0–98.5% of total N2O in the soil profile. Heterotrophic denitrification (HD) was the main process generating N2O, contributing between 53.4 and 96.6%, the remainder being due to ammonia oxidation pathways, which was further confirmed by metagenomics and quantitative polymerase chain reaction (qPCR) assays. Nitrifier denitrification (ND) was an important N2O production source, contributing 0–46.6% of total N2O production, which showed similar trends with N2O emissions. Among physicochemical and biological factors, ammonium content and the ratio of total organic matter to nitrate were the main driving factors affecting the contribution ratios of the ammonia oxidation pathways and HD pathway, respectively. Moisture content and pH affect norC-carrying Spirochetes and thus the N2O production rate. These findings confirm the importance of ND to N2O production and help to elucidate the impact of anthropogenic activities, including tillage, fertilization, and irrigation, on N2O production

Interface Stabilization of Undercoordinated Iron Centers on Manganese Oxides for Nature-Inspired Peroxide Activation

Coordinatively unsaturated metal centers constitute a key element in natural catalytic cycles. Construction of analogues of these ensembles on heterogeneous supports may aid in the innovative development of artificial catalysts showing efficient and stable reaction patterns. We herein stabilized naturally prevalent undercoordinated iron (UCI) centers on manganese oxides via the interface confinement effect between transition-metal oxides. The created heterostructure showed efficient activation of peroxy-bonds containing peroxymonosulfate (PMS) molecules, with aqueous organic contaminant oxidation efficacy several times that of reference metal oxides. The combined spectroscopic, electrochemical, and in situ measurement results revealed that these interfacial oxygen-deficient UCI sites not only benefited thermodynamically favored PMS accumulation but also facilitated surface-to-surface electronic communication across atomic interface-bonding channels, thus providing a feasible platform to give rise to highly oxidizing (Fe, Mn)-oxo intermediates. Such PMS-activating metal centers in transitional states were sequentially reduced via either direct oxidation of organic substrates or electrophilic attack of other PMS molecules, with reactive singlet oxygen (¹O₂) generation. This reaction pattern guaranteed preservation of the catalyst structure after the reversible redox cycle, enabling a stable, kinetics-enhanced catalytic process

Sensory evaluation results of 4 types of nonsensate flaps.

<p>*, P<0.05, compared with the AVF group;</p>#<p>, P<0.05, compared with the SPBRA group;</p>†<p>, and P<0.05, compared with the UAPF group.</p><p>AVF: arterialized venous flap, SPBRA: superficial palmar branch of the radial artery, PIPF: posterior interosseous perforator flap, UAPF: ulnar artery perforator free flap, SWM: Semmes-Weinstein monofilament test, NS: normal sensation (filament level, 2.36–2.83), DLT: diminished light touch (filament level, 3.22–3.61), DPS: diminished protective touch (filament level, 3.84–4.31), LPS: loss of protective sensation (filament level, 4.56).</p