Parameterization of turbulent flux from bare-soil and undercanopy surfaces is imperative for modeling land-atmosphere interactions in arid and semiarid regions, where flux from the ground is dominant or comparable to canopy-sourced flux. This paper presents the major characteristics of turbulent flux transfers over seven bare-soil surfaces. These sites are located in arid, semiarid, and semihumid regions in Asia and represent a variety of conditions for aerodynamic roughness length (z 0m ; from Ͻ1 to 10 mm) and sensible heat flux (from Ϫ50 to 400 W m Ϫ2 ). For each site, parameter kB Ϫ1 [ϭln(z 0m /z 0h ), where z 0h is the thermal roughness length] exhibits clear diurnal variations with higher values during the day and lower values at night. Mean values of z 0h for the individual sites do not change significantly with z 0m , resulting in kB Ϫ1 increasing with z 0m , and thus the momentum transfer coefficient increases faster than the heat transfer coefficient with z 0m . The term kB Ϫ1 often becomes negative at night for relatively smooth surfaces (z 0m ϳ 1 mm), indicating that the widely accepted excess resistance for heat transfer can be negative, which cannot be explained by current theories for aerodynamically rough surfaces. Last, several kB Ϫ1 schemes are evaluated using the same datasets. The results indicate that a scheme that can reproduce the diurnal variation of kB Ϫ1 generally performs better than schemes that cannot.

61The Tibetan Plateau (TP), known as the "sensible heat pump" and the 62 "atmospheric water tower", modifies monsoon circulations and regional energy and 63 water cycles over Asia (Wu and Zhang 1998; Zhao and Chen 2001a; Wu et al. 2007; 64 Xu et al. 2008b; Zhou et al. 2009). Strong ascent over the TP may transport lower-65 tropospheric water vapor and anthropogenic pollutants into the upper troposphere-66 lower stratosphere (UT-LS), which exerts an influence on the local ozone valley 67 (Zhou et al. 1995; Liu et al. 2003; Bian et al. 2011) and the aerosol-layer 68 enhancements near the tropopause (Tobo et al. 2007; Vernier et al. 2015). The TP also In the 1990s, a longer-term field experiment was conducted over the TP with the 84 support of the Japanese Experiment on Asian Monsoon (JEXAM). It estimated the 2008a; Zhang et al. 2012; Chen et al. 2011 Chen et al. , 2013. It found diurnal variations of et al. 2013; Hu et al. 2014; Zheng et al. 2014 Zheng et al. , 2015a Zheng et al. , b, c, 2016 Guo et al. 2015; 161 Zhuo et al. 2016; Wan et al. 2017). These problems may also cause large uncertainties 162 in reanalysis datasets and satellite products (such as air temperature, soil moisture, 163 surface heat fluxes, and radiation) over the TP (Li et al. 2012; Wang et al. 2012; Zhu 164 et al. 2012; Su et al. 2013; Zeng et al. 2016). 165To promote Tibetan meteorological research, the Third Tibetan Plateau 166Atmospheric Scientific Experiment (TIPEX-III), to continue for eight to ten years, OBJECTIVES. 173The field observational objective of TIPEX-III is to constitute a 3-D observation 174 system of the land surface, PBL, troposphere, and lower stratosphere over the TP. 175This system integrates ground-, air-, and space-based platforms based on the 176 meteorological operational networks, the TIPEX-III network, the existing NIOST (Fig. 1a). Consistent with the operational observations of the 265 CMA, at each site the measurement system measures soil water content ( Fig. 1a). The regional network consists of 33 sites over 270 Naqu (Fig. 1c), which began operating in August 2015, and 17 sites over Shiquanhe This network consists of six additional sites at Bange, Namucuo, Anduo, Nierong, 280Jiali, and Biru, and contributes to integrated research on the high-resolution land-281 surface and PBL processes over the central TP and their effects on mesoscale systems. 282These observations have been conducted at Shiquanhe, Namucuo, Naqu, Anduo, Gongshan (98.67°E, 27.75°N) station on the southeastern slope of the TP (Fig. 1b), a 300 key area for gauging water-vapor transports from the Indian Ocean to East Asia. (Fig. 1b). A primary goal of these observations is to explore the cloud (Fig. 1b). A follow-up field campaign using ground-based radars Tuotuohe, Mangya, Golmud, and Xining meteorological stations (Fig. 1b). Using PRELIMINARY ACHIEVEMENTS OF TIPEX-III. 328The implementation of TIPEX-III has enhanced the monitoring capability for the 380(1) Cloud diurnal variation and warm rain process. 3...

Numerical land surface models (LSMs) are abundant and in many cases highly sophisticated, yet their output has not converged towards a consensus depiction of reality. Addressing this matter is complicated by the huge number of possible combinations of input land characteristics, forcings, and physics packages available. The Global Land Data Assimilation System (GLDAS) and its sister project the Land Information System (LIS) have made it straightforward to test a variety of configurations with multiple LSMs. In order to compare the impacts of the choice of LSM, land cover, soil, and elevation information, Corresponding author: Matt Rodell, Hydrological Sciences Branch, Code 614.3, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. Email: Matthew.Rodell@nasa.gov ( 2007, Meteorological Society of Japan and precipitation and downward radiation forcing datasets on simulated evapotranspiration, sensible heat flux, and top layer soil moisture, a set of experiments was designed which made use of high quality, physically coherent, 1-year datasets from four reference sites of the Coordinated Enhanced Observing Period (CEOP) initiative. As in previous studies, it was shown that the LSM itself is generally the most important factor governing output. Beyond that, evapotranspiration seems to be most sensitive to precipitation, land cover, and radiation (in that order); sensible heat flux is most sensitive to radiation, precipitation, and land cover; and soil moisture is most sensitive to precipitation, soil, and land cover. Various seasonal and model specific dependencies and other caveats are discussed. Output fields were also compared with observations in order to test whether the LSMs are capable of simulating an observed reality given a plausible set of inputs. In general, that potential was fair for evapotranspiration, good for sensible heat flux but problematic given its strong sensitivity to the inputs, and poor for soil moisture. The results emphasize that improving the LSMs themselves, and not just the inputs, will be essential if we hope to model land surface water and energy processes accurately.

DEAD-box proteins comprise a large protein family with members from all kingdoms and play important roles in all types of processes in RNA metabolism. In this study, a rice gene OsBIRH1, which encodes a DEAD-box RNA helicase protein, was cloned and characterized. The predicted OsBIRH1 protein contains a DEAD domain and all conserved motifs that are common characteristics of DEAD-box RNA helicases. Recombinant OsBIRH1 protein purified from Escherichia coli was shown to have both RNA-dependent ATPase and ATP-dependent RNA helicase activities in vitro. Expression of OsBIRH1 was activated in rice seedling leaves after treatment with defence-related signal chemicals, for example benzothiadiazole, salicylic acid, l-aminocyclopropane-1-carboxylic acid, and jasmonic acid, and was also up-regulated in an incompatible interaction between a resistant rice genotype and the blast fungus, Magnaporthe grisea. Transgenic Arabidopsis plants that overexpress the OsBIRH1 gene were generated. Disease resistance phenotype assays revealed that the OsBIRH1-overexpressing transgenic plants showed an enhanced disease resistance against Alternaria brassicicola and Pseudomonas syringae pv. tomato DC3000. Meanwhile, defence-related genes, for example PR-1, PR-2, PR-5, and PDF1.2, showed an up-regulated expression in the transgenic plants. Moreover, the OsBIRH1 transgenic Arabidopsis plants also showed increased tolerance to oxidative stress and elevated expression levels of oxidative defence genes, AtApx1, AtApx2, and AtFSD1. The results suggest that OsBIRH1 encodes a functional DEAD-box RNA helicase and plays important roles in defence responses against biotic and abiotic stresses.

P-Arylation in water has been developed via cross-coupling of aryl halides with diphenylphosphine oxide (Ph(2)P(O)H) and (R(P))-(-)-menthyl benzylphosphinate catalyzed by NiCl(2)·6H(2)O/Zn under relatively mild conditions.

Drought has been a concern in global and regional water, carbon, and energy cycles. From 1999 to 2011, northern China experienced a multiyear precipitation reduction that significantly decreased water availability as indicated by the Palmer Drought Severity Index and soil moisture measurements. In this study, a light use efficiency model (EC-LUE) and an ecosystem physiological model (IBIS) were used to characterize the impacts of long-term drought on terrestrial carbon fluxes in northern China. EC-LUE and IBIS models showed the reduction of averaged GPP of 0.09 and 0.05 Pg C yr ), Tianjing (1923 kg ha À1 yr À1 ), and Heilongjiang (1791 kg ha À1 yr À1 ), and the maize yield anomaly was significantly correlated with the annual precipitation over the entire study area. Our results revealed that recent climate change, especially drought-induced water stress, is the dominant cause of the reduction in the terrestrial carbon sink over northern China.

No abstract

Nitrous oxide (N 2 O) fluxes from a cotton field in northern China were measured for a year using the static chamber method based on a gas chromatograph (GC) and the eddy covariance (EC) technique based on a tunable diode laser (TDL). The aims were to compare the N 2 O fluxes obtained from both techniques, assess the uncertainties in the fluxes and evaluate the annual direct emission factors (EF d s, i.e. the loss rate of fertilizer nitrogen via N 2 O emission) using the year-round datasets. During the experimental period, the hourly and daily mean chamber fluxes ranged from 0.6 to 781.8 and from 1.2 to 468.8 g N m −2 h −1 , respectively. The simultaneously measured daily mean EC fluxes varied between −10.8 and 912.0 g N m −2 h −1. The EC measurements only provided trustworthy 30-min fluxes during high-emission period (a 20-day period immediately after the irrigation that followed the nitrogen fertilization event). A reliable comparison was confined to the high-emission period and showed that the chamber fluxes were 17-20% lower than the EC fluxes. This difference may implicate the magnitude of systematic underestimation in the fluxes from chamber measurements. The annual emission from the fertilized cotton field was estimated at 1.43 kg N ha −1 yr −1 by the chamber observations and 3.15 kg N ha −1 yr −1 by the EC measurements. The EF d s calculated from the chamber and EC data were 1.04% and 1.65%, respectively. The chamber-based estimate was very close to the default value (1.0%) recommended by the Intergovernmental Panel on Climate Change. However, the difference in the EF d s based on the two measurement techniques may vary greatly with changing environmental conditions and management practices. Further comparison studies are still needed to elucidate this issue.