Significant increases of heavy precipitation and decreases of light precipitation have been reported over widespread regions of the globe. Global warming and effects of anthropogenic aerosols have both been proposed as possible causes of these changes. We examine data from urban and rural meteorological stations in eastern China (1955China ( -2011 and compare them with Global Precipitation Climatology Project (GPCP) data and reanalysis data in various latitude zones to study changes in precipitation extremes. Significant decreases in light precipitation and increases in heavy precipitation are found at both rural and urban stations, as well as low latitudes over the ocean, while total precipitation shows little change. Characteristics of these changes and changes in the equatorial zone and other latitudes suggest that global warming rather than aerosol effects is the primary cause of the changes. In eastern China, increases of annual total dry days (28 days) and 10 consecutive dry days (36%) are due to the decrease in light precipitation days, thereby establishing a causal link among global warming, changes in precipitation extremes, and higher meteorological risk of floods and droughts. Further, results derived from the GPCP data and reanalysis data suggest that the causal link exists over widespread regions of the globe.

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We provide a novel design of atmosphere visibility measurement system with the contrast principle used in the naked eye visibility observation. The new digital photography visiometer system (DPVS), composed of a CCD camera and two identical targets, utilizes the contrast of dual targets to measure the visibility. Two operational modes are designed to enable the DPVS to accommodate the lighting conditions of the day and night. Two passive targets, black bodies, are employed for daytime visibility measurement, and two active lights, LED panels, are utilized for nighttime. The mathematical models of the dual targets for both daytime and nighttime are developed, and the sensitivity analysis shows the requirements of the hardware to achieve desired accuracy. The design of the target including the blackbody and the LED panel is briefly discussed, and the temperature dependence and stability of the LED panels are measured experimentally. Finally, the DPVS is compared with two commercial visibility devices, a forward scatter meter and a transmission meter for field validation. A 5-day comparative experiment shows that the measurements of the DPVS generally well agree with those of the transmissometer and the forward scatter meter for visibility up to 15 km, and the relative bias of 87% of the DPVS measurements lies between −0.2 and 0.2. K E Y W O R D Sblack body, CCD camera, digital photography visiometer system, LED, visibility

Destructive earthquakes are mostly located in the active fault zones. The underground gas anomalies result to basically be consistent with the inferred distribution of active fault systems. Among them, radon is the earliest used as the effective prediction index of fault zone earthquake prediction. In this paper, radon concentrations in groundwater from the Longxian – Baoji fault zone in the Northwestern China are analyzed. Results show that the NW sector has a lower radon concentration (∼12 Bq/L) than that of the SE sector (40 ∼ 50 Bq/L). It indicated that the connectivity between the shallow and deep crust is relatively poor in the NW sector, which is not conducive to the upward diffusion and migration of deep fluids. Given that there is a seismic gap with no rupture of M ≥ 61/2 strong earthquake in the NW sector, it can be infered that the NW sector of the Longxian - Baoji fault zone has a higher risk of strong earthquakes than that in the SE sector.

In his comments, Wang cites a number of works to dispute the conclusion in our previous work, which attributes the observed decreases/increases in light/heavy precipitation in eastern China primarily to global warming rather than the regional aerosol effect. However, most of the cited works (admittedly, including our previous work), employ correlation analysis, which has little bearing on the cause-effect relationship. Theoretical analyses and/or modeling studies are needed to ascertain the cause-effect relationship. We argue that theoretical analyses and modeling results show that global warming is the primary cause of the widely observed phenomena of suppression of light precipitation and enhancement of heavy precipitation across the globe, including in eastern China.