Microphysical sensitivity of coupled springtime Arctic stratocumulus to modelled primary ice over the ice pack, marginal ice, and ocean
Microphysical sensitivity of coupled springtime Arctic stratocumulus to modelled primary ice over the ice pack, marginal ice, and ocean
复制标题
春季北极层积云对冰袋、边缘冰和海洋上模拟原生冰耦合的微物理敏感性
DOI：
10.5194/acp-17-4209-2017
复制
发表时间：
2016
影响因子：
6.3
通讯作者：
T. Choularton
中科院分区：
文献类型：
--
作者：
G. Young;P. Connolly;Hazel M. Jones;T. Choularton
摘要。本研究使用大涡模拟来测试欧洲北极地区单层混合层积云对原始冰数浓度的敏感性。考虑了北极气溶胶-云耦合和气候相互作用（ACCACIA）活动的观测结果，以便与使用大涡模式（LEM, UK Met）模拟的云微物理进行比较。办公室)。我们发现云结构对冰数浓度非常敏感，微小的增加会导致持续的混合相云结冰和破裂。通过灵敏度模拟和与海冰、边缘冰带和海洋观测结果的比较，确定了对Nice的三个关键依赖。在海冰上，我们发现沉积-凝结冰形成速率被高估，导致云冰川作用。当冰的形成仅限于水饱和条件时，我们发现在所有考虑的表面上的微物理可与飞机观测相媲美。我们表明，当使用DeMott等人（2010）和Cooper（1986）的初级冰核参数化时，MIZ上空的热过冷（- 13 °C）混合相云可以得到合理的精度模拟。在海洋上空，我们发现北极层对尼斯有很强的敏感性。Cooper（1986）的参数化在较低的环境温度下表现不佳，导致相对较高的尼斯（云顶温度为2.43 L−1，约为- 20 °C）和云冰川作用。使用DeMott等人（2010）的参数化方法，预测的Nice（在- 20 °C时为2.07 L−1）的小幅下降导致混合相条件在海洋上空持续24 小时。然而，这种表现导致对流结构的形成，通过降雪减少云中的液态水，通过耗尽的液相促进云的破裂。进一步降低Nice（0.54 L−1，使用来自ACCACIA观测的关系）可以使混合相条件保持至少24 h，并且在液体和冰水路径中具有更高的稳定性。在低数值浓度下，对尼斯的敏感性也很明显，DeMott等人（2010）预测的0.1 ×尼斯参数化导致模式内雨带的形成；雨带也会消耗云层中的液态水，促进云层破裂。
Abstract. This study uses large eddy simulations to test the sensitivity of single-layer mixed-phase stratocumulus to primary ice number concentrations in the European Arctic. Observations from the Aerosol-Cloud Coupling and Climate Interactions in the Arctic (ACCACIA) campaign are considered for comparison with cloud microphysics modelled using the Large Eddy Model (LEM, UK Met. Office). We find that cloud structure is very sensitive to ice number concentrations, Nice, and small increases can cause persisting mixed-phase clouds to glaciate and break up. Three key dependencies on Nice are identified from sensitivity simulations and comparisons with observations made over the sea ice pack, marginal ice zone (MIZ), and ocean. Over sea ice, we find deposition–condensation ice formation rates are overestimated, leading to cloud glaciation. When ice formation is limited to water-saturated conditions, we find microphysics comparable to aircraft observations over all surfaces considered. We show that warm supercooled (−13 °C) mixed-phase clouds over the MIZ are simulated to reasonable accuracy when using both the DeMott et al.(2010) and Cooper(1986) primary ice nucleation parameterisations. Over the ocean, we find a strong sensitivity of Arctic stratus to Nice. The Cooper(1986) parameterisation performs poorly at the lower ambient temperatures, leading to a comparatively higher Nice (2.43 L−1 at the cloud-top temperature, approximately −20 °C) and cloud glaciation. A small decrease in the predicted Nice (2.07 L−1 at −20 °C), using the DeMott et al.(2010) parameterisation, causes mixed-phase conditions to persist for 24 h over the ocean. However, this representation leads to the formation of convective structures which reduce the cloud liquid water through snow precipitation, promoting cloud break-up through a depleted liquid phase. Decreasing the Nice further (0.54 L−1, using a relationship derived from ACCACIA observations) allows mixed-phase conditions to be maintained for at least 24 h with more stability in the liquid and ice water paths. Sensitivity to Nice is also evident at low number concentrations, where 0.1 × Nice predicted by the DeMott et al.(2010) parameterisation results in the formation of rainbands within the model; rainbands which also act to deplete the liquid water in the cloud and promote break-up.
登录
查看更多内容
ACCACIA 活动期间春季和夏季北极层积云云微物理特性的观测和比较
影响因子：
6.3
作者：
Lloyd G
通讯作者：
Lloyd G
影响因子：
6.3
作者：
G. Young;Hazel M. Jones;E. Darbyshire;K. Baustian;J. McQuaid;K. Bower;P. Connolly;M. Gallagher;T. Choularton
通讯作者：
G. Young;Hazel M. Jones;E. Darbyshire;K. Baustian;J. McQuaid;K. Bower;P. Connolly;M. Gallagher;T. Choularton
COPE期间云微物理和冰形成的观测
DOI：
10.5194/acpd-15-16049-2015
发表时间：
2015
期刊：
--
影响因子：
--
作者：
Taylor J
通讯作者：
Taylor J
影响因子：
6.3
作者：
Crosier, J.;Bower, K. N.;Blyth, A. M.
通讯作者：
Blyth, A. M.
观测到的北极混合相云从海冰过渡到公海时的微物理变化
影响因子：
6.3
作者：
Young G
通讯作者：
Young G