A New Method to Compare Hourly Rainfall between Station Observations and Satellite Products over Central–Eastern China

This study employs a newly defined regional-rainfall-event （RRE） concept to compare the hourly charac- teristics of warm-season （May September） rainfall among rain gauge observations, China merged hourly pre- cipitation analysis （CMPA-Hourly）, and two commonly used satellite products （TRMM 3B42 and CMORPH） By considering the rainfall characteristics in a given limited area rather than a single point or grid, this method largely eliminates the differences in rainfall characteristics among different observations or measure- ments over central-eastern China. The results show that the spatial distribution and diurnal variation of RRE frequency and intensity are quite consistent among different datasets, and the performance of CMPA- Hourly is better than the satellite products when compared with station observations. A regional rainfall coefficient （RRC）, which can be used to classify local rain and regional rain, is employed to represent the spatial spread of rainfall in the limited region defining the RRE. It is found that rainfall spread in the selected grid box is more uniform during the nocturnal to morning hours over central-eastern China. The RRC tends to reach its diurnal maximum several hours after the RRE intensity peaks, implying an in- termediate transition stage from convective to stratiform rainfall. In the afternoon, the RRC reaches its minimum, implying the dominance of local convections on small spatial scale in those hours, which could cause large differences in rain gauge and satellite observations. Since the RRE method reflects the overall features of rainfall in a limited region rather than at a fixed point or in a single grid, the widely recognized overestimation of afternoon rainfall in satellite products is more reliable in representing sub-daily variation of rainfall a reasonable method to compare satellite products with which also has great potential to be used in evaluating the numerical models. not obvious, and thus the satellite estimates are from the RRE perspective. This study proposes rain gauge observations on the sub-daily scale, spatiotemporal variation of cloud and rainfall in

Temperature characteristics research of SOI pressure sensor based on asymmetric base region transistor

Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors（R_1, R_2, R_3 and R_4/locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator（SOI） wafer by micro electromechanical system（MEMS） technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity（TCS） for the sensor before and after temperature compensation are -1862 and -1067 ppm/℃, respectively. Through varying the ratio of the base region resistances r_1 and r_2, the TCS for the sensor with the compensation circuit is -127 ppm/℃. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor.