Variation Characteristics Of Negative Air Ion Concentration In Diaoluoshan Tropical Rainforest And Their Relation With Meteorological Elements

Negative Air Ion Concentration(NAIC) and meteorological elements(rainfall,wind velocity,air temperature,relative humidity)are determined in the Diaoluoshan Tropical Rainforest. NAIC diurnal variation in different seasons, NAIC seasonal variation, and their relation with meteorological elements are analyzed. Then,NAIC under fog and rainy conditions and their relation with meteorological elements are analyzed. Also, the NAIC healthcare functions of Diaoluoshan rainforest are preliminary explored. The results show that:(1) NAIC is the greatest in summer, followed by spring and autumn, and the lowest in winter. Diurnal variation curves of spring, summer and autumn are similar to ‘M’, the two peaks reach at about 9:00-10:00 and 15:00-16:00, respectively, the trough emerge at about 12:00. Diurnal variation curve of winter is similar to single peak wave, the peak reach at around 15:00, the trough 12:00-13:00. In summer, NAIC and wind velocity are negatively related, NAIC and relative humidity are positively related; in autumn, there is a positive relationship between NAIC and air temperature, relative humidity; no significant relationship is found between NAIC and the determined meteorological elements.(2)Tropical rainforest NAIC has a positive correlation with rainfall intensity; the Lenard effect occurs when raindrops are crashing with the leaves, trunks and soil in the tropical rain forest during precipitation process. Rainforest NAIC and rainfall change are positively correlated, the greater change in precipitation the greater change the NAIC and vice versa. If the intensity of rainfall is relatively low(rainfall intensity less than or equal to 2mm within 15 min), there is no difference between NAIC under non-rainy weather conditions(i.e. sunny, cloudy and overcast); no difference in the NAIC was found under non-rainy conditions. There is no significant relationship between NAIC and air temperature and wind speed under rainy conditions.(3) NAIC under Mist conditions is significantly higher than that of sunny and other fog conditions with higher intensity. As the intensity of fog getting greater from fog to super thick fog, NAIC shows a slightly downward trend, however, the decline is not statistically significant. There is a positive relationship between NAIC and air temperature under fog conditions, i.e., the higher temperature is, the greater the NAIC will be, and vice versa. There is no significant relationship between NAIC and wind velocity under foggy conditions.(4) Daytime in spring, summer and autumn, NAIC of Diaoluoshan tropical rainforest benefits to human beings’ health. On summer daytime, the rainforest has the greatest beneficial effects to health. In contrast, the beneficial effects are much weaker in winter, while most of the winter daytime, NAIC can sustain basic health.Suggestions of NAIC health benefits exploitation are presented in the last section of the paper in order to provide a reference for making full use of rainforest eco-tourism resources and develop a higher level of forest tourism.