which cloud type starts appearing at 0.0 or lower?
Entity
m.0bw1t_
Cumulonimbus incus
class literal
meteorology.cloud 0.0^^http://www.w3.org/2001/XMLSchema#float
meteorology.cloud type.float
Cloud 0.0
none <=
meteorology.cloud.minimum_altitude
Minimum Altitude
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX : <http://rdf.freebase.com/ns/> 
SELECT (?x0 AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :meteorology.cloud . 
FILTER (?x1 <= "0.0"^^<http://www.w3.org/2001/XMLSchema#float>)
?x0 :meteorology.cloud.minimum_altitude ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND meteorology.cloud (le meteorology.cloud.minimum_altitude 0.0^^http://www.w3.org/2001/XMLSchema#float))