气候与环境研究
氣候與環境研究
기후여배경연구
Climatic and Environmental Research
2015年
6期
685-704
,共20页
梅海霞%沈新勇%王卫国%黄小梅
梅海霞%瀋新勇%王衛國%黃小梅
매해하%침신용%왕위국%황소매
微物理%单参数%单气柱模式%Milbrandt%2-mon方案%截距
微物理%單參數%單氣柱模式%Milbrandt%2-mon方案%截距
미물리%단삼수%단기주모식%Milbrandt%2-mon방안%절거
Microphysics%Single-moment%Single-column model%Milbrandt 2-mon scheme%Intercept
利用耦合Milbrandt 2-mon (MY)双参数微物理方案的WRF中的单柱模式，对TWP-ICE试验（Tropical Warm Pool International Cloud Experiment）期间的个例进行数值模拟和敏感性试验。通过与观测资料和云分辨率模式的模拟结果进行对比发现：MY 方案默认的双参数版本和单参数版本均能够再现 TWP-ICE 期间的热带云系的总体宏观和微观特征。MY方案的双参数版本模拟的降水率的演变特征同观测十分吻合，冰相粒子的微观特征同观测事实较为一致。单参数默认版本的降水率、液态云的构成及冰相粒子微观特征方面同观测事实存在明显差距。然而实际业务应用中单参数方案由于计算量较小应用更为广泛，但模拟效果有待改善。为了使方案保持计算量较为合理的同时具有较好的模拟效果，参考双参数控制试验中的冰相物质的微观特征，尝试对单参数方案中冰相粒子的单参数方法进行改进。冰晶单参数改进试验中虽然对于冰晶数浓度采用两种不同的处理方法，但模拟效果均未明显改善。其中冰云总含量更加接近观测，且冰云构成发生显著变化，主要归因于冰晶有效半径的减小间接削弱了雪和霰的发展。云滴含量的异常增强导致液态水含量比观测偏高约一个量级，暖云异常增厚则与上升运动的增强直接相关。雨水含量明显增强及雨滴有效半径减小综合导致了降水率仅有微弱改善。雪的单参数改进试验中，雪的截距值增加及环境场过饱和条件改善促进了冰云的发展。通过适当调整雪的截距的经验诊断公式，雪的截距、液态水含量以及降水率均得到较好的改善；而指定雪截距为常数的处理方式使液态云更为偏厚，降水率演变细节同观测仍然差异显著。改进试验结果表明，单参数方案中采用适当的经验公式诊断雪的截距的处理方法对改善单参数方案的模拟能力具有一定的可行性。
利用耦閤Milbrandt 2-mon (MY)雙參數微物理方案的WRF中的單柱模式，對TWP-ICE試驗（Tropical Warm Pool International Cloud Experiment）期間的箇例進行數值模擬和敏感性試驗。通過與觀測資料和雲分辨率模式的模擬結果進行對比髮現：MY 方案默認的雙參數版本和單參數版本均能夠再現 TWP-ICE 期間的熱帶雲繫的總體宏觀和微觀特徵。MY方案的雙參數版本模擬的降水率的縯變特徵同觀測十分吻閤，冰相粒子的微觀特徵同觀測事實較為一緻。單參數默認版本的降水率、液態雲的構成及冰相粒子微觀特徵方麵同觀測事實存在明顯差距。然而實際業務應用中單參數方案由于計算量較小應用更為廣汎，但模擬效果有待改善。為瞭使方案保持計算量較為閤理的同時具有較好的模擬效果，參攷雙參數控製試驗中的冰相物質的微觀特徵，嘗試對單參數方案中冰相粒子的單參數方法進行改進。冰晶單參數改進試驗中雖然對于冰晶數濃度採用兩種不同的處理方法，但模擬效果均未明顯改善。其中冰雲總含量更加接近觀測，且冰雲構成髮生顯著變化，主要歸因于冰晶有效半徑的減小間接削弱瞭雪和霰的髮展。雲滴含量的異常增彊導緻液態水含量比觀測偏高約一箇量級，暖雲異常增厚則與上升運動的增彊直接相關。雨水含量明顯增彊及雨滴有效半徑減小綜閤導緻瞭降水率僅有微弱改善。雪的單參數改進試驗中，雪的截距值增加及環境場過飽和條件改善促進瞭冰雲的髮展。通過適噹調整雪的截距的經驗診斷公式，雪的截距、液態水含量以及降水率均得到較好的改善；而指定雪截距為常數的處理方式使液態雲更為偏厚，降水率縯變細節同觀測仍然差異顯著。改進試驗結果錶明，單參數方案中採用適噹的經驗公式診斷雪的截距的處理方法對改善單參數方案的模擬能力具有一定的可行性。
이용우합Milbrandt 2-mon (MY)쌍삼수미물리방안적WRF중적단주모식，대TWP-ICE시험（Tropical Warm Pool International Cloud Experiment）기간적개례진행수치모의화민감성시험。통과여관측자료화운분변솔모식적모의결과진행대비발현：MY 방안묵인적쌍삼수판본화단삼수판본균능구재현 TWP-ICE 기간적열대운계적총체굉관화미관특정。MY방안적쌍삼수판본모의적강수솔적연변특정동관측십분문합，빙상입자적미관특정동관측사실교위일치。단삼수묵인판본적강수솔、액태운적구성급빙상입자미관특정방면동관측사실존재명현차거。연이실제업무응용중단삼수방안유우계산량교소응용경위엄범，단모의효과유대개선。위료사방안보지계산량교위합리적동시구유교호적모의효과，삼고쌍삼수공제시험중적빙상물질적미관특정，상시대단삼수방안중빙상입자적단삼수방법진행개진。빙정단삼수개진시험중수연대우빙정수농도채용량충불동적처리방법，단모의효과균미명현개선。기중빙운총함량경가접근관측，차빙운구성발생현저변화，주요귀인우빙정유효반경적감소간접삭약료설화산적발전。운적함량적이상증강도치액태수함량비관측편고약일개량급，난운이상증후칙여상승운동적증강직접상관。우수함량명현증강급우적유효반경감소종합도치료강수솔부유미약개선。설적단삼수개진시험중，설적절거치증가급배경장과포화조건개선촉진료빙운적발전。통과괄당조정설적절거적경험진단공식，설적절거、액태수함량이급강수솔균득도교호적개선；이지정설절거위상수적처리방식사액태운경위편후，강수솔연변세절동관측잉연차이현저。개진시험결과표명，단삼수방안중채용괄당적경험공식진단설적절거적처리방법대개선단삼수방안적모의능력구유일정적가행성。
A double-moment bulk microphysics scheme, Milbrandt 2-mon (MY), was evaluated using the WRF single-column model during the period of the Tropical Warm Pool International Cloud Experiment (TWP-ICE). Results from separate simulations using the double-moment and sample one-moment (1M) versions of the microphysics scheme with the default settings in WRF were able to reproduce the general characteristics of moisture variables from the macro to the micro scale, as compared with observations and cloud resolving model (CRM) results. The rain rate and microscale features of the ice phase from the double-moment control simulation (CTL) were very close to observations, but showed significant deviations from the sample 1M version simulation. One-moment bulk microphysics schemes have been widely applied in real business situations with little computation, but their simulating abilities need to be improved. In order to maintain a reasonable computational expense, but with better simulating ability, several measures were applied to improve the sample 1M versions of the MY scheme on the basis of the microscale features of the ice phase from CTL. The results from the runs with two ice 1M modified versions were similar. Both showed non-significant improvements, despite their different treatments in terms of the number concentration of ice crystals. The frozen water path and observations showed more agreement, but significant changes occurred in the composition of ice clouds, mainly attributed to the weakened growth of snow and graupel indirectly affected by smaller ice crystals. The liquid water path showed an order of magnitude larger than observations as a result of abnormal enhancement in cloud droplet content, related to enhancements in upward movement. The liquid water content and raindrop effective radius changing in an opposite direction led to a tiny improvement in the rain rate. Sensitivity tests using two snow 1M modified versions of the MY scheme showed that ice-phase cloud was enhanced after adding the snow intercept and improving the environmental conditions of superstation. The characteristics of the snow intercept, liquid water content, and rain rate became significantly improved after adjusting the empirical formula of the snow intercept properly. Meanwhile, the method of adopting the reference values of the snow intercept in CTL did not show the same performance in ice-phase clouds, resulting in thicker warm clouds and a significant discrepancy between the simulated and observed rain rate. Optimized simulations with 1M modified versions suggested that the treatment of adjusting the empirical formula of the snow intercept properly in the 1M version of the microphysics scheme has a certain feasibility.
