The conventional meteorological observation data, artificially enhanced observation data and NCEP/NCAR (the National Centers for Environmental Prediction and the National Center for Atmospheric Research) grid data were used to analyze the extreme rain and snow weather in Liaoning province from November 7-9, 2021. The results show that the Northeast China Cold Vortex (NCCV) and the surface cyclone are the main influence systems of the extreme rain and snow weather. The convergence of the middle and lower troposphere, the divergence of the upper troposphere and the convergence of the strong cold and warm air flow are the main causes of the extreme rain and snow weather. The coupling of the high and low level jet and the high level divergence suction, together with the dynamic lifting effect of the NCCV, the warm and wet low level jet climb along the cold pad, which further strengthen the upward motion. The warm moist jet provides abundant water vapor conditions for the extreme rain and snow weather, and the strengthening of the warm moist jet corresponds to the strengthening of water vapor convergence, combined with the dynamic lifting effect of the low-level cold pad and the NCCV, and the ground convergence line distributes along the terrain, which triggers the extreme heavy snow weather. Terrain blocking leads to the accumulation of cold air on the ground to form cold air cushion, which is an important reason for extreme snowfall. The difference of temperature stratification is the main reason for the difference of rain and snow phase between Anshan and Xiuyan. The low layer cold air cushion with the characteristics of freezing layer provides favorable temperature stratification conditions for the extreme snowstorm in Anshan. The melting layer thickness and ground temperature are the key factors for the occurrence of freezing rain in Xiuyan.

Based on the sliding centroid method, the spatial rainfall location forecast performance of EC model in 24~168 h for moderate, heavy, and torrential rainfall in the front and warm areas of South China was analyzed. The results show that the ECMWF model (abbreviated as EC model) has systematical meridional and zonal deviation in warm-area rainfall and front rainstorm location, and the forecasted rainfall location is located west and north to the observed one. The location deviation of front moderate rain and heavy rain is dominantly meridional ones, in which cases with north rainfall deviation are more than the south one. The zonal displacement error is not clear. The meridional deviation of front and warm-area rainfall location lies in 1.0° and 1.5°, respectively. The zonal deviation lies in 1.5ånd 2.0°, respectively. The spatial rainfall location forecast performance of EC model is different with the different valid time, which is relatively stable in 24~72 h. The forecast deviation in 96~168 h increases obviously. A method for correcting the spatial rainfall location is established. The deviation correction method is applied to two rainfall events in 2022, and the results show that the TS scores can be significantly improved.

Using hourly precipitation data from 84 national meteorological stations in Heilongjiang province from 1991 to 2021, we analyzed the spatiotemporal distribution of conventional precipitation and hourly heavy precipitation processes. The results show that the precipitation process in Heilongjiang province mainly occurred in the afternoon to evening. The spatial distribution of precipitation was closely related to the terrain. The precipitation center was located in the middle of the Lesser Khingan Mountains, the eastern Songnen Plain, and the western Sanjiang Plain. The hourly heavy precipitation process mainly occurred in the southwestern and central regions of Heilongjiang province, and the distribution of hourly heavy precipitation extreme values were consistent with the distribution of heavy precipitation frequency. The annual variation in hourly average precipitation and precipitation frequency in Heilongjiang province from 1991 to 2021 decreased first and then increased, and the average intensity of hourly precipitation first increased and then decreased. From 2006 to 2021, the average intensity of hourly precipitation decreased, whereas the precipitation frequency increased significantly, resulting in an increase in precipitation year by year. The monthly variations in hourly average precipitation, precipitation frequency, and average intensity of hourly precipitation all reached their peaks in July. The daily variation of hourly average precipitation and the average intensity of hourly precipitation were both largest in the afternoon. Hourly heavy precipitation mainly occurred in the afternoon, with the highest frequency at 15:00.

Based on the hourly precipitation data from 1115 automatic weather stations and and terrain height data in the central and southern regions of Hebei province from June to August of the years 2013-2020, we statistically analyzed the distribution of occurrence frequency, duration, and precipitation intensity during hourly heavy rainfall (HHR) events and rainstorm days in summer. The results show that in summer over the central and southern regions of Hebei province, the contribution rate of HHR with an occurrence frequency of 2.2 to 3.0 times per year was greater than 35%. There were six high-frequency areas for HHR, which were mainly distributed along the eastern coast of Cangzhou in a patchy pattern and in the western mountainous areas in a spot pattern. The diurnal variation in occurrence numbers of HHR less than 60 mm·h^-1 at all stations was characterized by the unimodal pattern. The occurrence numbers of HHR above 60 mm·h^-1 at all stations decreased with the increase of precipitation intensity and did not exhibit an obvious diurnal variation. In terms of precipitation properties, the convective precipitation due to cumulus was dominant at the high-HHR-frequency regions over the western mountainous areas of the central and southern Hebei province, which mostly occurred from 12:00 to 18:00. The eastern coast of Cangzhou was mostly affected by typhoons and shear lines, and HHR belonged to mixed precipitation due to stratiform clouds and cumulus clouds, usually with intense heavy precipitation.

Using daily surface precipitation and temperature data from 62 stations in Heilongjiang province from 1961 to 2021 and the National Centers for Environmental Prediction/the National Center for Atmospheric Research (NCEP/NCAR) reanalysis data, we statistically analyzed the characteristics of Northeast China Cold Vortex (NCCV) that lasted 3 days or more during the spring sowing period and its impact on climatic factors. The results show that a total of 233 NCCV events occurred on a total of 958 days during the spring sowing periods of 61 years. The occurrence frequency and day numbers of NCCV exhibited an increasing trend, and the occurrence frequency of NCCV had a significantly negative correlation with the duration of a single cold vortex. The precipitation contribution of NCCV was about 43.29%, and the frequency of heavy precipitation days and rainstorm days during NCCV processes was relatively high, being 48.66% and 59.46%, respectively. The NCCV had no significant impact on air temperature during the spring sowing period. At 500 hPa geopotential height field, there was a good positive correlation between the NCCV and the blocking high area from Lake Baikal to Okhotsk Sea. More than 30% of the NCCV activities were accompanied by the Okhotsk blocking high. The Okhotsk blocking high enhanced the cold vortex precipitation, but had no significant effect on the low temperature during the NCCV process.

The data of Hainan lightning location monitoring network from 2008 to 2017 were used to analyze the characteristics of lightning activity triggered by typhoons landing in Hainan Island. The spatio-temporal distribution characteristics of lightning activity of typhoons on land and offshore in Hainan Island and its relationship with typhoon intensity and path change were analyzed, and the changes of lightning activity before and after typhoon landing were compared. The results show that the South China Sea summer monsoon is closely related to the lightning activity of typhoons landing in Hainan. The stronger the cold air activity, the weaker the lightning activity, and the stronger the sea temperature, the stronger the lightning activity. The lightning activity of the landing typhoon is relatively strong in summer, gradually weakening in autumn, and the weakest in spring. The spatial distribution of lightning activity was the most in the northwest quadrant of the typhoon center, followed by the northeast quadrant and the southeast quadrant. The typhoon center is more in the north than in the south, and in the north, the northwest is more than the northeast, and the southeast is the least. The lightning activity was more on the left side than on the right side of the typhoon moving direction, and the lightning activity was more on the left side than on the left side. The average lightning frequency of most typhoons is greater than that of land when the center of the typhoon is at sea. A few typhoons are accompanied by lightning outbreak during the landing and sailing stages, and some typhoons have spatial distribution conversion of lightning activity before and after landing. There is no obvious correlation between the intensity of lightning activity on land and offshore caused by typhoon landing on Hainan Island and the intensity of typhoon. The outbreak of lightning has a certain indication effect on the continuous enhancement or maintenance of the intensity of typhoon before landing.

Using hourly temperature observation data from 89 automatic meteorological stations in urban development areas of Wuhan city from June to August of 2022, this study analyzes the temperature variations under different weather conditions in summer among three types of spaces (urban, agricultural, ecological) in the region. It explores the spatial distribution of air temperature in these three types of spaces during heatwave events and the impact of ecological and agricultural spaces on the air temperature in urban spaces. The results show that, for all three types of spaces, the lowest average hourly air temperatures are recorded from 05:00 to 06:00, and the highest from 14:00 to 16:00, indicating a diurnal variation trend. Heatwave events significantly increase the nighttime air temperatures in all three types of spaces, with the urban areas experiencing the largest increase of 4.5 ℃. The difference in air temperatures among the three types of spaces is greatest on hot days and smallest on rainy or overcast days. Significant spatial heterogeneity in the distribution of nighttime air temperatures exists on both hot and non-hot days, forming a concentric structure of air temperatures that decrease from the central urban areas towards the outskirts. The difference in daytime air temperatures among the three types of spaces is relatively small. On both hot and non-hot days, the cooling effects of ecological and agricultural spaces on their adjacent urban spaces are most significant around sunrise and at night, with the intensity of cooling stronger on hot days than on non-hot days.

Utilizing hourly air negative oxygen ion and meteorological observation data from Tianjin city in 2020, the variations in air negative oxygen ion concentrations (ANOIC) across different seasons and weather conditions within three typical functional areas, i. e. forests, wetlands, and urban zones and their relationships with meteorological elements were investigated. The results indicate that the ANOIC is highest in forests, followed by wetlands, and lowest in urban areas, with the ranking for seasons being summer > spring > autumn > winter. The ANOIC is highest on rainy days and lowest on snowy days. The ANOIC in forests on clear days is slightly higher than on foggy days, whereas those in wetlands and urban areas are slightly lower on clear days compared to foggy days. The diurnal variation of ANOIC is bimodal, with the amplitude of variation following the sequences of forests>wetlands>urban areas, and summer > spring > autumn > winter. Overall, ANOIC shows a positive correlation with temperature, relative humidity, vapor pressure, and the amount of precipitation in the past 24 hours, but a negative correlation with atmospheric pressure. The relationship between ANOIC and visibility differs across the different functional areas, while the correlation with wind speed is not significant. The relationship between ANOIC and meteorological elements varies across different seasons and weather conditions. In urban areas, the ANOIC is significantly influenced by human activities, making its variability more complex compared to forests and wetlands, and its correlation with meteorological elements is weaker on the whole.

Utilizing a dataset comprised of 630 winter wheat samples collected from He′nan province during the years 2008, 2010 to 2014, and 2019, along with corresponding meteorological data, this study employs multiple comparison methods and logistic multivariate regression analysis to construct meteorological indicators predicting the attainment of grade two or higher grain quality in winter wheat. The results indicate a significant negative correlation between the thousand kernel weight (TKW) of winter wheat grains and average air relative humidity during the anthesis period, and a significant positive correlation with sunlight duration. The proportion of shriveled grains shows a significant positive correlation with air relative humidity, precipitation amount, and the number of precipitation days. The correlation between winter wheat grain quality and decadal meteorological factors displays dynamic variations. Key meteorological factors affecting the TKW of winter wheat grains differ by region within He′nan province, with sunlight and temperature being critical in the northern part, temperature in the eastern part, and temperature combined with precipitation in the southern part. The evaluation of meteorological indicators for winter wheat grain quality matched well with the actual grain quality grades, yielding a consistency rate of 84%, while the consistency rate for the evaluation of shriveled grains reached 100%. Over the past 30 years, the average frequency of attaining at least grade two in terms of meteorological conditions for winter wheat quality in He′nan province has been 79.7% (with the exception of western He′nan), suggesting that meteorological conditions are overall favorable for the improvement of grain quality of winter wheat in He′nan province.

The quality characteristics of 8 varieties of rice in Panjin area in 2022 were analyzed. The correlation between processing quality, appearance quality, cooking and taste quality, nutritional quality of rice grains and original spectral reflectance, first derivative spectrum, continuum removed spectrum of the rice canopy at maturity were also examined. The results show that Yanjing 939 has better processing quality; Jindao 106 (Line 9) has better appearance quality; Jindaoxiang 103 has better cooking quality; Panjing 968 (Line 3) has better nutritional quality. The correlation between raw spectral reflectance and brown rice rate is good with correlation coefficients reaching at 0.767 in the wavelength bands of 731~1131 nm and 1150~1360 nm. The correlation between brown rice rate and the first derivative spectrum is best reaching a highly significant level at 1459 nm with a correlation coefficient of 0.867. The correlations between chalkiness degree, chalky grain rate and continuum-removed reflectance are better at 1804 nm, reaching a significant negative correlation with correlation coefficients of -0.979 and -0.983, respectively. The correlation between length-width ratio and the original spectrum is good with the highest correlation coefficient of 0.849 at 659 nm. The taste value contained in cooking quality, the amylose content, and the protein content included in nutritional quality all show good correlation with continuum removed spectrum.

Using observation data from automatic meteorological stations, ADTD lightning positioning, and Doppler radar, we analyzed the intensity, spatiotemporal distribution and synoptic patterns of thunderstorm gust over the central and western Bohai Sea from 2018 to 2021. Based on the ERA5 reanalysis data and observation data from automatic meteorological stations, we also studied the characteristics and reference thresholds of physical quantities before the occurrence of widespread thunderstorms gust. The results indicate that the thunderstorm gust in the central and western Bohai Sea were mainly within the levels of 8 to 9, mostly occurred in the western and southern coastal areas of Bohai Sea, in June and July and in the early night. Among the thunderstorm gust events that lasted for 4 hours or more, the widespread thunderstorm gust events accounted for 86%. The synoptic systems at 500 hPa triggering thunderstorm gust were classified as the cold vortex type (46%), the high-level trough type (37%), the subtropical high edge type (12%), and the northwesterly flow type (5%). There was an obvious dry layer in the middle troposphere before the occurrence of widespread thunderstorm gust. When applying physical parameter thresholds for forecasting, the impact of synoptic systems and seasonal climate features needs to be considered.

Utilizing weather data from 7 national meteorological stations and 157 regional automatic weather stations, DEM, and township tea plantation area data from 1960 to 2022 in Xuancheng city, Anhui province, based on the principle of natural disaster risk assessment, using the indexes of frost hazard, spring tea vulnerability, exposure factor and employing methodologies such as the cloud model, analytic hierarchy process (AHP) and natural breaks method, this research conducts zoning analysis of frost damage risk for spring tea considering hazard index, index weights, and comprehensive risk grading. The results indicate that from 1960 to 2022, the main occurrences of frost damage to spring tea in Xuancheng city was under the conditions of daily minimum temperatures ranging from -4 ℃ to 4 ℃, and mountains areas has significantly higher comprehensive frost damage risks relative to plains. Mild frost damage is primarily found in the northern parts of Xuancheng, including Xuanzhou district and Guangde city, while moderate frost damage is mainly distributed in the southern and northern townships of Guangde city. Severe and extremely severe frost damage chiefly occurs in large parts of Ningguo city, Tingxi township in Jing county, Xikou town in Xuanzhou district, and townships such as Yangtan, Baidian, Sihe, and Lucun in Guangde city.

This study uses the Shangdianzi national background station in Beijing to represent the background area in North China, and adopts the Ozone Source Appointment Technology (OSAT) method of the CAMx model to analyze the ozone source contribution in North China background areas from June 25 to July 31, 2019. A simulation study of O₃ concentration was conducted to quantify the contribution of different source components and tagging regions, aiming to deeply analyze the source composition of ground-level O₃ concentration in the background area of North China. The components that contribute to the ground O₃ concentration in this region, from high to low, were boundary transport (61.8%), source transport (31.8%), background concentration (3.3%), and local generation (3.1%). The main source tagging regions from high to low were were Hebei province (5.70%), Inner Mongolia autonomous region (5.43%), and Shandong province (4.48%). The source categories were civil source (15.35%), agricultural source (10.72%), transportation source (7.21%), and industrial source (1.62%), and the main precursors were NO_x (29.6%) and VOCs (5.3%). The ground ozone concentration in North China background area is mainly contributed by boundary transport and source transport, which further validates the rationality for Shangdianzi station as an atmospheric background station.

Utilizing hourly wind speed observation data from eight national meteorological stations in the western region of Jilin province from 2012 to 2021, the wind shear power law formula was used to extrapolate specific wind speed thresholds corresponding to three conditions of non-operation, full capacity operation, and cut-out wind power generation at the observation heights of the weather stations. The statistical analysis was conducted of the annual total duration, continuous duration, and yearly variability of these specific wind speeds and their climatic characteristics, as well as assessing their impact on wind power generation. The results indicate that the western region of Jilin province possesses favorable wind energy resources, characterized by high annual average wind speeds, a high occurrence frequency of full capacity wind speeds, and a short duration of non-operation wind speeds, implying infrequent wind speed conditions unfavorable for wind power generation. The best wind resources in this region were observed from March to May, with higher monthly average wind speeds. Relatively favorable wind resources were concentrated in January, July, August, and December, with comparatively lower monthly average wind speeds and longer duration of non-operation wind speeds. The least specific wind speeds conducive for wind power generation occurred in February, May, and June. In the eastern parts of the western Jilin province, the wind resources were relatively unprominent, with lower annual average wind speeds compared to the western parts, longer periods of non-operation wind speeds, a lower frequency of full capacity wind speeds, and virtually no occurrences of cut-out wind speeds.