基于《环北极地区多年冻土和地下冰状态图》的中国及其周边地区冻土分布图（2001）

字段说明：
Num_code（冻土属性编码）
Combo（冻土属性）
extent（冻土范围）
content（含冰量）

属性对照如下：
（1）冻土属性对照表：
0 （No information ）
1 - chf （Continuous permafrost extent with high ground ice content and thick overburden）
2 - dhf （Discontinuous permafrost extent with high ground ice content and thick overburden）
3 - shf （Sporadic permafrost extent with high ground ice content and thick overburden）
4 - ihf （Isolated patches of permafrost extent with high ground ice content and thick overburden ）
5 - cmf （Continuous permafrost extent with medium ground ice content and thick overburden ）
6 - dmf （Discontinuous permafrost extent with medium ground ice content and thick overburden ）
7 - smf （Sporadic permafrost extent with medium ground ice content and thick overburden ）
8 - imf （Isolated patches of permafrost extent with medium ground ice content and thick overburden）
9 - clf （Continuous permafrost extent with low ground ice content and thick overburden ）
10 - dlf （Discontinuous permafrost extent with low ground ice content and thick overburden ）
11 - slf （Sporadic permafrost extent with low ground ice content and thick overburden ）
12 - ilf （Isolated patches of permafrost extent with low ground ice content and thick overburden）
13 - chr （Continuous permafrost extent with high ground ice content and thin overburden and exposed bedrock ）
14 - dhr （Discontinuous permafrost extent with high ground ice content and thin overburden and exposed bedrock ）
15 - shr （Sporadic permafrost extent with high ground ice content and thin overburden and exposed bedrock ）
16 - ihr （Isolated patches of permafrost extent with high ground ice content and thin overburden and exposed bedrock）
17 - clr （Continuous permafrost extent with low ground ice content and thin overburden and exposed bedrock ）
18 - dlr （Discontinuous permafrost extent with low ground ice content and thin overburden and exposed bedrock ）
19 - slr （Sporadic permafrost extent with low ground ice content and thin overburden and exposed bedrock）
20 - ilr （Isolated patches of permafrost extent with low ground ice content and thin overburden and exposed bedrock ）
21 - g （Glaciers）
22 - r （Relict permafrost）
23 - l （Inland lakes ）
24 - o （Ocean/inland seas ）
25 - ld （Land）

（2）冻土范围对照表
c = continuous (90-100%)
d = discontinuous (50- 90%)
s = sporadic (10- 50%)
i = isolated patches ( 0 - 10%)

（3）含冰量对照表
h = high (>20% for "f" landform codes) (>10% for "r" landform codes)
m = medium (10-20%)
l = low (0-10%)