Temporal and Spatial Aerosol Dynamics On Shore and Inland Using Continuous Ceilometers - Aerosol Profiles Retrieval

1. RAYMOND AND BEVERLY SACKLER FACULTY OF EXACT SCIENCES DEPARTMENT OF GEOPHYSICS AND PLANETARY SCIENCES הפקולטה למדעים מדויקים ע"ש ריימונד ובברלי סאקלר החוג לגאופיסיקה ולמדעים פלנטריים Temporal and Spatial Aerosol Dynamics On Shore and Inland Using ContinuousCeilometers Aerosol Profiles Retrieval Department of Geosciences Smadar Egert ,Leenes Uzan, Pavel Kunin,Pinhas Alpert smadare85@gmail.com, leenesu@gmail.com WLMLA VIII April 2015

2. Introduction A Ceilometer is a federated compact LIDAR instrument for cloud height measurements. Methods to retrieve the MLH and follow aerosol migration using ceilometers are under development world wide Ceilometer CL31

3. Ceilometers deployment in Israel Israel location: 29-33°N, on the Mediterranean eastern side & border of the southern desert belt. It has two major seasons: winter & summer with short passage periods. Its south belongs to the desert and north to subtropical climate regions A Ceilometer network provides aerosol vertical monitoring over Israel 24/7 All the stations will provide a sparse 3D spatial aerosol map including MLH structure. The network is build gradually the first stations: sea shore and 7 km inland will be presented. IDF (permanent) IMS (permanent) IAA (permanent) ATEP (seasonally)

4. Atmospheric mixed layer height (MLH) Daily ML pattern-Theory Clear daytime Pattern close to theory cloudy Sun does not heat the ground -ML evolution is suppressed Partially cloudy Sunset: residual layer + new ML

5. Atmospheric mixed layer height (MLH) retrieval algorithm ML Height Retrieval using Wavelet Covariance Transform (WCT): • Perform convolutions of the LIDAR signal with the edge sharpening Haar function described in b). • Repeat the process for various dilation values a until the WCT function shown in c) reaches the maximum peak value • The ML Height will be b. • If there is an isolated layer like clouds c) will have a double peak shown in d) LIDAR signal b WCT Peak H. Baars, A. Ansman, R. Engelman, D. Althousen “Continous monitoring of boundary layer top with a Lidar”At. Chem & Phys. 8 2008 d)

6. Atmospheric mixed layer height (MLH) retrieval algorithm A cloud on the entrainment zone Inversion

7. ML retrieval algorithm- special cases of clouds within the ML There are rare special cases of high concentration sub layers within the MLH. These events need a modification of the WCT method to define the ML height at the layer top and not on the high concentration center The MLH will be defined using the a WCT peak above the negative /positive peak

8. Summer in Israel The Israeli summer is characterized by 3 typical synoptic states: 4- Weak Persian trough 5- Medium Persian trough 8-High to the west. There is a distinct daily pattern – high from sunrise, a decreases due to sea breeze penetration, rising again close to sunset and remaining as a residual layer during the night. The peak hour and details of daily pattern are affected by the synoptic state Lap-3000 acoustic RADAR (Hadera) IMS Ceilometer (Beit Dagan) • The main physical characteristics creating the patterns result in similar MLH behavior for the two instruments and two locations • There is an annual and local variability in the patterns even during a defined synoptic states

9. Ceilometer vs. Radiosonde MLH for Bet Dagan & Tel Aviv Sonde launched only twice a day in Bet Dagan (BD) The correlation between ML height derived from Sonde and Ceilometer seems lower in TLV Is there a reason to expect a differences between a shore station and a 7km inland? The answer is YES due to different periods of summer cloudiness and slight differences in the hour te wind turns from the north- west daily sea breeze to eastern land breeze at night

10. Ceilometer MLH for Bet Dagan & Tel Aviv Tel Aviv (shoreline) Beit Dagan ( 7 km from shoreline)

11. Winter time in Israel characteristics: 1. Lows from west-rain 2. Cold high from north 3. Strong easterly winds Easterly wind example Very low aerosol concentration Most of the aerosols can be found on the lowest 100m. The first Ceilometer bean can give the ground level daily trend Tel Aviv 16.12.2013

12. Spring Time in Israel Dust Penetration- March 2014 02.02.2014 03.02.2014 01.02.2014 Aeronet During 2/3 particles in all heights were mainly dust (large particles > 10µ) During 3/3 particles on 850mb had a different origin (can be land / sea misxtur: small-medium size

13. Spring Time Dust Penetration- March 2014 • Temporal “lag” • Density might be under ceilometer threshold Does not exist. Model spatial resolution is too low MLH500m TLV 2.3.2014 20 min average Beit Dagan Sde-dov

14. Spring Time Dust Penetration- March 2014 WRF-CHEM MODEL Can be the additional European aerosols predicted by Hysplit model

15. Conclusions The ML Height can be verified from the aerosol evolution 24/7. The retrieval algorithm was refined to include clouds, high concentration aerosol sub regions and lofted layers directly The Ceilometers network is a promising tool to study the 3D aerosol evolution over Israel. Even the 2 stations, on shore and 7km inland, reveal the differences in the evolution of the ML, cloudiness and dust The network provides a tool to study and enhance dynamical and dust model performance. The dust case shown reveals lofted dust layer that were not retrieved by the model and can be a risk to aviation for a few hours We wish to thank the Israeli Meteorological Service and the Israeli Air force for the Ceilometers data and collaboration.