Assessing the impact of radioactive iodine on humans subsequent to a nuclear accident requires a better understanding of its behaviour in the environment. An original approach aimed at developing a model constrained by data collected during experimental campaigns has been developed. These experimental campaigns, named MIOSEC 2 and MIOSEC 3 respectively, were conducted in the middle of grassland. They are based on emissions of gaseous elemental iodine (I2) into the atmosphere above the grassland to determine the dry deposition velocities of iodine on the grass and to model these velocities as a function of the environmental conditions, particularly wind friction velocity, sensible heat flux, and stomatal resistance. The measured dry deposition velocities were between 0.02 and 0.49 cm s-1 during MIOSEC 2, varying by more than one order of magnitude, and between 0.48 and 1.25 cm s-1 during MIOSEC 3. The dry deposition model for iodine developed as a result of these experiments relies on the micrometeorological characteristics of the atmospheric surface layer, the pertinent physical and chemical properties of the iodine and the surface properties of the grass; all these parameters were measured at the time of the experiments. Given the experimental conditions, the modelled dry deposition velocities varied between 0.11 and 0.51 cm s-1 during MIOSEC 2 and between 0.31 and 1.6 cm s-1 during MIOSEC 3. The dry deposition model for iodine indicates that the variations in deposition velocity are induced by the mechanical turbulence, since there is significant correlation between the dry deposition velocities of iodine and the wind friction velocities on grass. The model also shows that the higher deposition velocity values during MIOSEC 3 are due to the fact that the stomata were more open during the experiments. There is also significant correlation between the experimental results and modelled values both for MIOSEC 2 (R2 = 0.61) and for MIOSEC 3 (R2 = 0.71).

中文翻译：

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测量和模拟环境中草上气态元素碘（I2）的干沉降速度。

评估核事故后放射性碘对人类的影响需要更好地了解其在环境中的行为。已经开发出旨在开发受实验活动期间收集的数据约束的模型的原始方法。这些实验活动分别称为MIOSEC 2和MIOSEC 3，在草原中部进行。它们基于向草地上方的大气中排放气态元素碘（I2），以确定碘在草地上的干沉降速度，并根据环境条件对这些速度进行建模，尤其是风摩擦速度，显热通量和气孔阻力。在MIOSEC 2期间测得的干沉降速度在0.02至0.49 cm s-1之间，变化幅度超过一个数量级，在MIOSEC 3期间介于0.48和1.25 cm s-1之间。这些实验的结果是，碘的干沉积模型依赖于大气表层的微气象特征，碘的相关理化性质和表面性质。草的 所有这些参数都是在实验时测量的。在实验条件下，模拟的干沉积速度在MIOSEC 2期间介于0.11和0.51 cm s-1之间，在MIOSEC 3期间介于0.31和1.6 cm s-1之间。碘的干沉积模型表明诱发了沉积速度的变化。由于机械湍流，由于碘的干沉降速度与草地上的风摩擦速度之间存在显着的相关性。该模型还显示，在MIOSEC 3期间较高的沉积速度值是由于在实验期间气孔更开放的事实所致。对于MIOSEC 2（R2 = 0.61）和MIOSEC 3（R2 = 0.71），实验结果与模型值之间也存在显着相关性。