Boundary-Layer Characteristics of Persistent Regional Haze Events and Heavy Haze Days in Eastern China

Table 1

Surface and high-pressure conditions on heavy haze days.

Series	Types	Date (yyyy-mm-dd)	500 hPa	850 hPa	Stations recording heavy haze days	Stations recording haze days
1	EQP	1987-12-26	Southwest	Equalizing zone	4	7
2		1992-10-28	West	Equalizing zone	3	6
3		1994-04-28	Northwest	Equalizing zone	3	7
4		1998-12-27	Northwest to west	Equalizing zone	3	7
5		2001-11-21	West	Equalizing zone	3	8
6		2001-11-22	West	Equalizing zone	3	7
7		2002-02-05	Northwest to west	Equalizing zone	3	7
8		2005-10-26	Northwest to southwest	Saddle	3	8
9		2007-04-06	West	Equalizing zone	3	8
10		2008-07-17	Equalizing zone	Saddle	3	5
11		2008-11-01	West	Equalizing zone	3	6
12		2012-03-06	Southwest to west		3	8
13	ACF	1981-12-28	West	Saddle	3	8
14		1985-11-16	West	Equalizing zone	3	8
15		1990-10-15	Northwest	Equalizing zone	3	8
16		1999-10-28	West		3	8
17		2002-12-31	Northwest	Inverted trough	3	8
18		2003-12-12	Northwest	Equalizing zone	3	6
19		2003-12-16	Northwest	Base of cold vortex	3	7
20		2003-12-17	Northwest	Base of cold vortex	3	8
21		2009-01-09	Northwest to west		3	8
22		2010-11-21	Front of trough	Base of trough	3	7
23		2011-01-23	Northwest to west	Equalizing zone	3	5
24		2012-01-20	West	Equalizing zone	3	8
25	BOH	1992-01-25	West	Equalizing zone	3	8
26		2005-10-18	West	Equalizing zone	3	8
27		2008-03-11	West	Backside of the high pressure	3	8
28		2009-11-26	West	Backside of the high pressure	3	6
29		2011-10-08	West	Backside of the high pressure	3	6
30	BAH	1987-12-24	West	Equalizing zone	3	6
31		1992-01-27	Northwest	Equalizing zone	4	8
32		1992-05-31	Equalizing zone	Equalizing zone	3	6
33		1992-11-14			3	6
34		1996-04-26	Northwest		3	8
35		1999-11-21	West		3	8
36		2005-10-31	West	Equalizing zone	3	6
37		2008-04-18	Southwest	Backside of the high pressure	3	6
38		2008-10-15	Southwest to west	Equalizing zone	3	8
39		2011-06-13	West	Equalizing zone	4	6
40	INT	1984-04-26	Northwest to southwest	Equalizing zone	3	7
41		1992-01-28	Northwest	Equalizing zone	3	8
42		1994-11-11	Northwest to southwest	Equalizing zone	3	6
43		2004-02-19	Front of ridge	Backside of the high pressure	3	8
44		2004-05-10	Front of ridge	Backside of the high pressure	3	8
45		2009-11-08	Southwest to west	Saddle	3	7
46	Others	2002-01-03	Northwest		3	5
47		2003-06-25	Equalizing zone	Saddle	3	8
48		2004-11-07	West	Equalizing zone	4	8
49		2008-05-26	Northwest	Equalizing zone	4	8
50		2011-06-03	Equalizing zone	Equalizing zone	3	7

Equalized pressure: EQP, advancing edge of a cold front: ACF, base of high pressure: BOH, backside of high pressure: BAH, and inverted trough: INT.